Using a combination of Co, Mo, and Pt oxides along with graphene nanoribbon and MoSe2 as efficient catalysts for OER and HER

To make it commercially available for use in electricity production, hydrogen is required to be stored for roughly one to four decades. Through the application of the green energy technique, hydrogen used in fuel cells can be obtained from electrolysers. Platinum group metals (PGMs) are normally used to electrocatalyse the reactions, such as hydrogen and oxygen evolution reactions (HER and OER) and oxy-gen reduction reaction (ORR), which occur in fuel cells and electrolysers. This work reports the develop-ment and application of electrocatalysts with suitable properties using Co and Mo oxides with or without MoSe2 and in combination or not with graphene nanoribbons (GNRs), which are capable of supporting low amount of Pt and are highly efficient for OER and HER. Based on the results obtained, CoMoSe/GNR was found to be the best and most stable electrocatalyst for OER. The improvements observed in OER eletrocatalytic properties were attributed to the synergistic effects of binary metal ions, including Co2 +, Co3 +, Mo4 +, and Mo6+ (transition metals intercalated across the nanostructures, with Co2+ and Mo4+ act -ing as active sites), as well as the interactions between the metals and ion support (geometric effects, charge transfer) and between the different oxides em ployed. PtCoMo was found to be the best and most stable electrocatalyst for HER. The improvements observed in HER properties were attributed to the pres-ence of Pt0 and Pt2 +metal/ions supported on CoMo structures - the strong interaction between Pt and Co/Mo oxides on PtCoMo nanocomposites interface produced electron-deficient Pt delta+ species - and the synergistic effects involving the Pt metal/ions and the binary metal ions, including Co2 +, Co3 +, Mo4 +, and Mo6+ (transition metals intercalated across the nanostructures), in the reaction process. A significantly low amount of Pt (4.5 mu gPt cm -2) was used for the construction of the PtCoMo/CP electrode. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Hydrogen needed for electricity production is stored for around one to four decades, and can be obtained from electrolysers using green energy techniques. Platinum group metals are commonly used to catalyse reactions in fuel cells and electrolysers, with Co and Mo oxides, MoSe2, and graphene nanoribbons being used to develop efficient electrocatalysts for OER and HER.