No abstract

Effective design of high-performance electrocatalysts for the green synthesis of hydrogen peroxide (H2O2) by a two-electron oxygen reduction reaction (2e-ORR) method is of vital importance in various applications, but it is still a great challenge for the electrocatalysis community after all of these years. In this work, a novel ZnSnO3 perovskite is prepared as a highly selective and stable catalyst for the electrosynthesis of H2O2 via 2e-ORR. Profiting from its perovskite-type structure, it presents excellent electrochemical activity toward 2e-ORR in an alkaline electrolyte, and correlated H2O2 selectivity can reach 76%. Additionally, the H2O2 selectivity of ZnSnO3 perovskite in 2e-ORR can be steadily maintained for 6 h in a durability test, and the production of H2O2 synthesis achieves a total amount of 78 mmol·gcat –1·h–1 at 0.1 V. Impressively, ZnSnO3 perovskite delivers a preferable turnover frequency (TOF) of 1.31 × 10–3 s–1 compared to the commercial Pt/C catalyst (0.05 × 10–3 s–1) under the same conditions, demonstrating the great applicable potential of ZnSnO3 perovskite as an active non-noble metal oxide electrocatalyst for 2e-ORR. From the view of catalytic essence, the high electrochemical performance of ZnSnO3 perovskite in 2e-ORR originates from the suitable adsorption capacity on its surface for the adsorption of important *OOH intermediates according to the theoretical calculations. Therefore, ZnSnO3 perovskite as the efficient 2e-ORR catalyst is a promising candidate for the green synthesis of hydrogen peroxide.

No abstract

Voltage reversal of proton exchange membrane fuel cells caused by hydrogen deficiency seriously deteriorates the anodes and lowers their performance and lifetime. A commonly used method is to add oxygen evolution reaction catalysts (e.g., IrO 2 ) to the anode to extend the water electrolysis plateau against harmful carbon corrosion. Herein, strongly connected IrO x nanoparticles (SC-IrO x ) are prepared by removing the low surface area carbon carrier of the as-synthesized Ir/C catalyst. The reversal-tolerant anode with SC-IrO x owns an anti-reversal time of 9.32 h, which is 3.2 and 4.4 times that of the reversal-tolerant anode with commercial IrO x and weakly connected IrO x , respectively. Further transmission electron microscope characterizations reveal that SC-IrO x can construct a stable electron and proton transport pathway in the anode catalyst layer, which can delay the isolation of oxygen evolution reaction catalyst from the electron and proton conducting network, thus extending the water electrolysis plateau. Herein, our findings suggest that tuning the microstructures of IrO x catalysts is indeed an effective and promising approach to extend the water electrolysis plateau and alleviate the performance degradation of proton exchange membrane fuel cells during the voltage reversal process.