Article
Chemistry, Analytical
Swarna P. Mantry, Biswaranjan D. Mohapatra, Rajesh K. Behera, Kumar S. K. Varadwaj
Summary: We investigated the electrochemical activity of transition metal ion doped MnOx@N-graphene hybrid catalysts for oxygen reduction reaction (ORR). The doped catalysts showed significantly improved performance compared to the undoped catalyst. The Fe-doped catalyst exhibited the highest positive shift in onset potential, highest electron transfer number, and lowest peroxide yield. The Co-doped catalyst showed the highest current density, comparable to benchmark Pt/C catalyst.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2022)
Article
Nanoscience & Nanotechnology
Sandip K. Pahari, Yit-Tsong Chen
Summary: This study investigates the formation of intermediates in electrocatalyst-assisted water splitting using a bifunctional mechanism, and confirms the role of functionalized carboxylates in improving catalytic efficiency through pH-dependent and isotope labeling experiments.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Environmental
Chen Wang, Yuepeng Liu, Zhongfang Li, Likai Wang, Xueliang Niu, Peng Sun
Summary: The 2D Fe, N-codoped graphene (2D Fe-NG) was prepared using a nitrogen-containing polymer (ABPBI), Fe salts, and a cationic surface-active agent treated montmorillonite (CMMT) layer template. The addition of Fe3+ in the form of Fe-N-x bonds formed by coordination with N species of ABPBI in MMT contributes to the excellent ORR performance in O-2-saturated 0.1 M KOH electrolyte and close-to-RuO2 OER performance. The self-made ZAB based on 2D Fe-NG demonstrates high peak power density, excellent rechargeable performance, and higher DC cycling stability.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Inorganic & Nuclear
Yun-Wu Li, Shi-Kun Su, Cai-Zhen Yue, Jun Shu, Peng-Fang Zhang, Fang-Hui Du, Su-Na Wang, Hui-Yan Ma, Jie Yin, Xin Shao
Summary: The study designed a hierarchical Fe3O4@MnOx nano-composite with improved electrocatalytic performance and overall water splitting efficiency by introducing a pH-regulated redox reaction.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Physical
Yuepeng Liu, Wenjie Duan, Hongchang Pei, Peng Sun, Yinggang Sun, Yanqiong Zhuang, Zhongfang Li
Summary: A Fe, Co, N, and S co-doped three-dimensional porous graphene-like catalyst (FeCo-N,S-G) is prepared using a dual template strategy, which exhibits excellent catalytic activity for oxygen reduction and evolution reactions as well as hydrogen evolution reaction. The porous structure of the catalyst facilitates high-density active site exposure and mass transfer, leading to high performance in homemade aqueous and all-solid-state flexible zinc-air batteries.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Chemistry, Inorganic & Nuclear
Alvaro Seijas-Da Silva, Victor Oestreicher, Eugenio Coronado, Gonzalo Abellan
Summary: In this study, MgFe-based LDH phases were selected as model systems to investigate the effect of Fe-clustering on the OER performance. The results showed that samples with a lower Fe-clustering degree exhibited better electrocatalytic performance.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Physical
Yuepeng Liu, Zhongfang Li, Likai Wang, Lei Zhang, Xueliang Niu
Summary: In this study, Fe/N co-doped three-dimensional porous graphene was successfully prepared via a template method and showed promising potential as bifunctional electrocatalysts for oxygen reduction reaction and oxygen evolution reaction. The catalyst exhibited pH-independent ORR activity and low OER overpotential in alkaline electrolyte, leading to excellent performance in Zn-air batteries.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Nanoscience & Nanotechnology
Young Jin Sa, Sohee Kim, Yesol Lee, Ji Man Kim, Sang Hoon Joo
Summary: In this study, four different mesoporous manganese oxides were synthesized and used as model catalysts to investigate the effects of local structures and Mn valence states on the activity of oxygen electrocatalysis. The results showed that for the oxygen reduction reaction, m-Mn2O3 exhibited the highest activity, followed by m-MnO2, m-MnO, and m-Mn3O4. For the oxygen evolution reaction, m-MnO2 showed the highest activity, followed by m-Mn2O3, while m-MnO and m-Mn3O4 had lower activity. These findings suggest that high-valent Mn species and disordered atomic arrangements induced by nanostructuring significantly affect electrocatalysis.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Electrochemistry
Hui Liu, Jiaxi Zhang, Hongjie Fang, Jiefeng Huang, Xiaohan Wu, Xuehua He, Juemin Song, Zheng Li, Yang Yan, Wanli Xu, Kun Yu
Summary: Different forms of delta-MnO2 with reduction sites anchored on non-supports or other supports were studied for their morphology, composition, and electrochemical properties. Results showed that the MnO2/rGO-2 layered hybrid exhibited higher BET surface area, superior adsorption performance, and lower charge-transfer resistance compared to other hybrids, especially showing excellent long-term durability. This suggests that the MnO2/rGO-2 hybrid could be a promising cathode catalyst for a mechanically reusable Mg-air battery with minimal decay over time.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Dusan Mladenovic, Elif Das, Diogo M. F. Santos, Ayse Bayrakceken Yurtcan, Scepan Miljanic, Biljana Sljukic
Summary: In this study, Pt and Pt-M (M = Ni, Fe, Cu) nanoparticles supported on graphene nanoplatelets (GNPs) were synthesized by simultaneous supercritical carbon dioxide deposition method. The morphology analysis revealed the formation of uniformly distributed metal nanoparticles on GNPs, and the XPS analysis determined their oxidation states. PtFe/GNPs exhibited favorable kinetics in both ORR and OER, and its performance was comparable to or even better than that of commercial Pt/C electrocatalyst.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Biochemistry & Molecular Biology
Anup Paul, Kristina Radinovic, Susanta Hazra, Dusan Mladenovic, Biljana Sljukic, Rais Ahmad Khan, Maria Fatima C. Guedes da Silva, Armando J. L. Pombeiro
Summary: The newly synthesized 3D coordination polymer Mn-CP showed good catalytic performance for oxygen reduction, with a distinct reduction peak observed in 0.1 M KOH but no activity in 0.5 M H2SO4. Additionally, it demonstrated significant activity towards oxygen evolution and hydrogen evolution in acidic media.
Article
Chemistry, Analytical
Tao Wang, Jing Feng, Qian Liu, Xiaofeng Han, Dongling Wu
Summary: A simple and green synthesis process for Fe/N-codoped reduced graphene oxide materials with high electrocatalytic activity for oxygen reduction reaction (ORR) was reported. The synthesized material exhibited superior performance and stability, showing promising potential for application in zinc-air batteries.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2022)
Article
Energy & Fuels
Dong Wook Kim, Beum Jin Park, Youngkwon Kim, Ho Seok Park
Summary: In this study, hierarchically structured Cr-doped NiCo-layered double hydroxides (LDHs) nanoplates chemically grown on the surface of nitrogen-doped reduced graphene oxide nanosheets (NiCoCr LDH/N-rGO) were reported for bifunctional electrocatalysts of RZABs. The electrocatalytic activity and kinetics of NiCoCr LDH/N-rGO for both ORR and OER were greatly improved due to Cr doping, resulting in lower overpotential and better Tafel's slope. As a result, the RZAB with NiCoCr LDH/N-rGO catalyst exhibited higher power density and better cycling stability compared to Pt/C+RuO2.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2023)
Article
Chemistry, Inorganic & Nuclear
Bang Lan, Heyi Zhong, Jueran Cao, Haiyan Chen, Zihao Zhou, Lei Zhang, Jingjing Duan, Ming Sun, Lin Yu
Summary: In this study, hollow alpha-MnO2 catalysts with abundant accessible active sites and enhanced intrinsic activity were successfully prepared and showed excellent electrocatalytic performance in rechargeable zinc-air batteries.
INORGANIC CHEMISTRY COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Saravanan Nagappan, Malarkodi Duraivel, SeongHoon Han, Mohammad Yusuf, Manjiri Mahadadalkar, KyeongMun Park, Amarajothi Dhakshinamoorthy, Kandasamy Prabakar, Sungkyun Park, Chang-Sik Ha, Jae-Myung Lee, Kang Hyun Park
Summary: Graphene, a two-dimensional material with a large surface area, is widely used in various fields. Recently, there has been increased focus on developing metal-free graphenes doped with heteroatoms as efficient electrocatalysts for oxygen reduction reactions (ORRs). Our study found that graphene prepared from graphene oxide (GO) by pyrolysis under a nitrogen atmosphere at 900 degrees C showed better ORR activity compared to pristine GO. Various pyrolysis conditions were tested, and the results suggest that the ORR electrocatalytic activity of graphene is influenced by these conditions. The prepared graphenes, particularly G100-1B and G100-2B, displayed promising ORR activity for fuel cell and metal-air battery applications.
Article
Chemistry, Multidisciplinary
Lars Banko, Emmanuel Batsa Tetteh, Aleksander Kostka, Tobias Horst Piotrowiak, Olga Anna Krysiak, Ulrich Hagemann, Corina Andronescu, Wolfgang Schuhmann, Alfred Ludwig
Summary: Polyelemental material systems, specifically high-entropy alloys, have unprecedented properties, but their exploration and exploitation is challenging due to the vast number of possible combinations. However, a method combining co-sputtering and shadow masking allows for the creation of microscale combinatorial libraries, which cover a wide range of compositions and enable high-throughput characterization. By applying this method, electrocatalytic activity maps for hydrogen evolution, oxygen evolution, and oxygen reduction reactions were obtained for two high-entropy alloy systems, identifying activity optima and lean compositions with low noble-metal content. This demonstrates the potential of these microlibraries as a discovery platform for polyelemental systems.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Changlong Wang, Yufeng Wu, Alexander Bodach, Moritz Lukas Krebs, Wolfgang Schuhmann, Ferdi Schueth
Summary: This study discusses the importance of hydrogen generated in electrolyzers for future energy scenarios. The standard anode reaction, oxygen evolution, is complex and requires high overpotential. The researchers have discovered a high-performance electrode based on earth-abundant elements, which can oxidize organic molecules at high current densities, providing a solution to the cost issue of hydrogen electrolysis and generating additional revenue.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Samuel V. Somerville, Peter B. O'Mara, Tania M. Benedetti, Soshan Cheong, Wolfgang Schuhmann, Richard D. Tilley, J. Justin Gooding
Summary: Enzymes with multiple active sites and control over the solution environment enable the formation of complex products from simple reactants. We mimic this concept using nanoparticles to facilitate the electro-chemical carbon dioxide reduction reaction. By altering the rate of CO2 delivery, the activity of the CO producing site, and the applied potential, we show that stable nanoparticles with lower CO formation activity can produce greater amounts of hydrocarbon products. This highlights the importance of the local solution environment and the stability of the catalyst in cascade reactions.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Wenhui He, Shubhadeep Chandra, Thomas Quast, Swapnil Varhade, Stefan Dieckhoefer, Joao R. C. Junqueira, Huimin Gao, Sabine Seisel, Wolfgang Schuhmann
Summary: Renewable electricity-powered nitrate reduction reaction (NO3RR) offers a net-zero carbon route to high ammonia (NH3) productivity. However, this route suffers from low energy efficiency due to the need for high overpotentials. A rational catalyst design strategy involving the assembly of Cu/Co nanophases into nanoribbons is suggested to alleviate this issue. Experimental studies show that the Cu-Co nanoribbons enable strong NO3- adsorption and rapid catalysis of NO3- to NH3, achieving a stable NO3RR with high current density and Faradaic efficiency.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Chenglong Luan, Johanna Angona, Arjun Bala Krishnan, Manuel Corva, Pouya Hosseini, Markus Heidelmann, Ulrich Hagemann, Emmanuel Batsa Tetteh, Wolfgang Schuhmann, Kristina Tschulik, Tong Li
Summary: We investigated the relationship between crystallographic orientations of beta-CoOOH and catalytic activity for the oxygen evolution reaction (OER). We found that beta-CoOOH(01 1? ${\bar{1}}$ 0) grown on [ 1?21? ${\bar{1}2\bar{1}}$ 0]-oriented Co exhibited higher OER activity compared to beta-CoOOH(10 1? ${\bar{1}}$ 3) grown on [02 2?1] ${\bar{2}1]}$ -oriented Co or beta-CoOOH(0006) grown on [0001]-oriented Co. This is due to the presence of higher amounts of hydroxyl ions and more easily reducible Co-III-O sites in beta-CoOOH(01 1? ${\bar{1}}$ 0). Our findings offer opportunities for designing pre-catalysts with preferred defects to promote the formation of the most active OER species.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
Bin Wu, Tianxiao Sun, Ya You, Haibing Meng, Dulce M. Morales, Mailis Lounasvuori, Abbas Beheshti Askari, Li Jiang, Feng Zeng, Baoshan Hu, Xiangzhi Zhang, Renzhong Tai, Zhichuan J. J. Xu, Tristan Petit, Liqiang Mai
Summary: Metal/nitrogen-doped carbons (M-N-C) are attractive oxygen electrocatalysts with low cost, tunable activity, and well-dispersed morphologies. In situ X-ray absorption spectroscopy (XAS) is a powerful characterization technique for studying the structure and properties of M-N-C catalysts under reaction conditions. This review provides an overview of XAS fundamentals and comprehensively discusses the setup, applications, and challenges of in situ XAS in catalysis. The review also highlights the investigation of active sites and structural evolution of M-N-C catalysts during oxygen electrocatalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
Carla Santana Santos, Bright Nsolebna Jaato, Ignacio Sanjuan, Wolfgang Schuhmann, Corina Andronescu
Summary: Scanning electrochemical probe microscopy (SEPM) techniques are used to study the local electrochemical reactivity of interfaces. Operando SEPM measurements involve using a SEPM tip to investigate electrocatalysts' performance while modulating the interface reactivity. This combination allows the correlation of electrochemical activity with changes in surface properties and provides insights into reaction mechanisms.
Article
Chemistry, Multidisciplinary
Joao R. C. Junqueira, Debanjan Das, Ann Cathrin Brix, Stefan Dieckhoefer, Jonas Weidner, Xin Wang, Jialin Shi, Wolfgang Schuhmann
Summary: Electrochemical CO2 conversion is a crucial technology for promoting the production of carbon-containing molecules and reducing CO2 emissions. This study reports a conceptual paired electrolyzer that can simultaneously produce formate at both the anode and cathode. The paired electrolyzer shows high selectivity and activity for formate production at high current densities, achieving a combined Faradaic efficiency for formate of 141% (45% anode and 96% cathode) at 200 mAcm(-2) current density.
Article
Chemistry, Physical
Moonjoo Kim, Emmanuel Batsa Tetteh, Alan Savan, Bin Xiao, Alfred Ludwig, Wolfgang Schuhmann, Taek Dong Chung
Summary: In this study, a method to evaluate the reorganization energy (?) of MEPBr2n+1 by scanning electrochemical cell microscopy (SECCM) was reported, which allows high throughput electrochemical measurements using a single electrode with high spatial resolution. The investigation of ? on a high-entropy alloy materials library composed of Pt, Pd, Ru, Ir, and Ag suggests a negative correlation between ? and the work function.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Electrochemistry
Ndrina Limani, Emmanuel Batsa Tetteh, Moonjoo Kim, Thomas Quast, Emmanuel Scorsone, Bruno Jousselme, Wolfgang Schuhmann, Renaud Cornut
Summary: Carbon-based nanomaterials are excellent candidates for oxygen reduction reaction (ORR) electrocatalysis due to their exceptional properties. However, investigating their intrinsic activity can be challenging using conventional methodologies. This study employs nano-scale scanning electrochemical cell microscopy (SECCM) to investigate individual catalyst agglomerates, providing high-resolution electrochemical information. The intrinsic ORR activity of the catalyst is revealed by normalizing the data based on their distinctive electrochemical surface area (ECSA). Additionally, the structure and morphology of the catalytically active agglomerates are visualized using scanning electron microscopy (SEM).
Article
Chemistry, Multidisciplinary
Anna Lielpetere, Kavita Jayakumar, Donal Leech, Wolfgang Schuhmann
Summary: Polymer coatings can protect redox polymer-based glucose biosensors from interference and prolong their functional lifetime. Different approaches were explored to protect against different interferents, and a multi-layer polymer design showed the best protection against AA, UA, and biological interferences.
Article
Electrochemistry
Nomnotho Jiyane, Enrique Garcia-Quismondo, Edgar Ventosa, Wolfgang Schuhmann, Carla Santana Santos
Summary: The integrity of the solid electrolyte interphase (SEI) on the negative electrode of lithium-ion batteries (LIB) is crucial for next-generation LIBs with silicon-carbon electrodes. The SEI protection is compromised by volume changes during Li ion de/intercalation, leading to irreversible degradation. Scanning electrochemical microscopy (SECM) is a useful technique for investigating the degradation mechanisms of advanced negative electrodes and revealing SEI surface reactivity heterogeneities after a few charge/discharge cycles.
BATTERIES & SUPERCAPS
(2023)
Article
Energy & Fuels
Michael Braun, Mohit Chatwani, Piyush Kumar, Yun Hao, Ignacio Sanjuan, Ariadni-Aikaterini Apostoleri, Ann Cathrin Brix, Dulce M. Morales, Ulrich Hagemann, Markus Heidelmann, Justus Masa, Wolfgang Schuhmann, Corina Andronescu
Summary: A mixed Co and Ni boride precursor was synthesized and annealed at different temperatures with or without the addition of the monomer benzoxazine (BO). The CoNiB annealed at 500 degrees C without BO showed the lowest overpotentials for alcohol oxidation reactions in alkaline electrolyte. The BO-containing catalyst exhibited enhanced electrocatalytic activity when pyrolysis was conducted at 400 degrees C.
JOURNAL OF PHYSICS-ENERGY
(2023)
Article
Electrochemistry
Swapnil Varhade, Gabriel Meloni, Emmanuel Batsa Tetteh, Monjoo Kim, Simon Schumacher, Thomas Quast, Corina Andronescu, Patrick Unwin, Wolfgang Schuhmann
Summary: Scanning electrochemical cell microscopy (SECCM) was used to investigate the interaction between aqueous alkaline electrolyte and a glassy carbon electrode surface. Numerical simulations were performed to study the impact of droplet geometry and size on the voltammetric signature. The study provides insights into droplet-surface interactions, which are crucial for a quantitative interpretation of SECCM measurements.
ELECTROCHIMICA ACTA
(2023)
Article
Chemistry, Multidisciplinary
Joao R. C. Junqueira, Debanjan Das, Ann Cathrin Brix, Stefan Dieckhoefer, Jonas Weidner, Xin Wang, Jialin Shi, Wolfgang Schuhmann
Summary: This study presents a conceptual paired electrolyzer that can simultaneously produce formate at high currents. By coupling CO2 reduction with glycerol oxidation, a BiOBr-modified gas-diffusion cathode and a NixB on Ni foam anode maintain their selectivity for formate in the paired electrolyzer compared to half-cell measurements. The paired reactor achieves a combined Faradaic efficiency for formate of 141% (45% anode and 96% cathode) at a current density of 200 mA cm(-2).
