Efficient electrocatalytic desulfuration and synchronous hydrogen evolution from H2S via anti-sulfuretted NiSe nanowire array catalyst

Decreasing energy consumption of water splitting strategy by replacing oxygen evolution reaction (OER) with more facile sulfide oxidation reaction (SOR) to H2 evolution and value-added sulfur products is a promising technology. Nevertheless, the unsatisfactory catalyst long-term stability and passivation issues substantially limit the overall productivity. Herein, we report an anti-sulfuretted NiSe nanowire array catalyst on nickel foam (NiSe/NF), this catalyst exhibits a significantly reduced anode potential of 0.49 V vs. RHE at 100 mA cm-2 compared to the oxygen evolution reaction (1.78 V vs. RHE) and remains admirable stability for more than 500 h without passivation. Particularly, the skillful combination of UV-vis, in situ Raman, and attenuated total reflection Fourier transform infrared spectra, we reveal that S2-/HS- has been selectively converted to Sn2-and by-product S2O32-rather than sulfur, which avoids long-perplexing passivation issue of solid sulfur. For the first time, we demonstrate the feasibility of the system (SOR + HER) in a commercial membrane electrode assembly stack, which affords 19.0 mL min-1 H2 at a low cell voltage of 1.0 V with consuming the electricity of 2.63 kWh Nm- 3 H2. This work provides a new avenue for low-cost H2 production by H2S electrooxidation desulfurization.

Automated summary

Replacing oxygen evolution reaction (OER) with sulfide oxidation reaction (SOR) is a promising technology for decreasing energy consumption in water splitting. However, catalyst stability and passivation issues limit productivity. In this study, an anti-sulfuretted NiSe nanowire array catalyst on nickel foam (NiSe/NF) showed a significantly reduced anode potential and remained stable for over 500 hours without passivation. By converting S2-/HS- to Sn2- and S2O32- instead of sulfur, the long-perplexing passivation issue was avoided. The feasibility of the SOR+HER system in a commercial membrane electrode assembly stack was demonstrated, providing low-cost H2 production by H2S electrooxidation desulfurization.