作者： | Zhiwei Liu,[a]Weijie Yuan,[a] Hongyuan Yang,[b] Zhenhui Kang,*[a]Mengjie Ma,[a] Prashanth W. Menezes,*[b,c] Ziliang Chen*[a,c] |
单位： | [a] Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, China. [b] Department of Chemistry: Metalorganics and Inorganic Materials, Technische Universität Berlin, Straße des 17 Juni 135, Sekr. C2, 10623 Berlin, Germany [c] Material Chemistry Group for Thin Film Catalysis – CatLab, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489 Berlin, Germany |
摘要： | The electrochemical oxygen reduction reaction (2e− ORR) offers a promising approach for H₂O₂ production, yet developing highly active, selective, and stable electrocatalysts remains a challenge. In this work, we present a phase reconstruction strategy to synthesize an oxalate-adsorbed nickel hydroxide electrocatalyst (Ni(OH)2-C2O4) through the self-dissociation of nickel oxalate in an alkaline medium, leading to a notable enhancement in H2O2 yield at elevated current densities. Remarkably, Ni(OH)2-C2O4 exhibits a 2e− selectivity exceeding 93% across a broad voltage range (0.0 to 0.5 V vs. RHE) in 0.1 M KOH, outperforming pristine Ni(OH)2. When deployed as a gas diffusion electrode in a flow cell, the Ni(OH)2-C2O4 catalyst demonstrates stable operation for 50 h at 200 mA cm−2, with a Faradaic efficiency surpassing 90% and a peak H2O2 yield of 6.2 mol g⁻¹cat h⁻¹. Comprehensive advanced characterizations, including in situ Raman spectroscopy, transient photovoltage spectra, and transient potential scanning spectra, coupled with post-ORR analyses, reveal that surface-adsorbed oxalate groups on Ni(OH)2 enhance the interfacial reaction kinetics between active Ni sites and reactants by inducing a charge trapping effect and forming ahydrogen bonded network, facilitating robust and high-yield H2O2 production. |
