Liu Chang, Li Hao, Chen Junsheng, Yu Zixun, Ru Qiang, Li Shuzhou, Henkelman Graeme, Wei Li, Chen Yuan
School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW, 2006, Australia.
Department of Chemistry and the Oden Institute for Computational and Engineering Sciences, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, TX, 78712, USA.
Small. 2021 Apr;17(13):e2007249. doi: 10.1002/smll.202007249. Epub 2021 Mar 10.
Decentralized electrosynthesis of hydrogen peroxide (H O ) via oxygen reduction reaction (ORR) can enable applications in disinfection control, pulping and textile bleaching, wastewater treatment, and renewable energy storage. Transition metal oxides are usually not efficient catalysts because they are more selective to produce H O. Here, it is shown that divalent 3d transition metal cations (Mn, Fe, Co, Ni, and Cu) can control the catalytic activity and selectivity of columbite nanoparticles. They are synthesized using polyoxoniobate (K HNb O ·13H O) and divalent metal cations by a hydrothermal method. The optimal NiNb O holds an H O selectivity of 96% with the corresponding H O Faradaic efficiency of 92% in a wide potential window from 0.2 to 0.6 V in alkaline electrolyte, superior to other transition metal oxide catalysts. Ex situ X-ray photoelectron and operando Fourier-transformed infrared spectroscopic studies, together with density functional theory calculations, reveal that 3d transition metals shift the d-band center of catalytically active surface Nb atoms and change their interactions with ORR intermediates. In an application demonstration, NiNb O delivers H O productivity up to 1 mol g h in an H-shaped electrolyzer and can yield catholytes containing 300 × 10 m H O to efficiently decomposing several organic dyes. The low-cost 3d transition-metal-mediated columbite catalysts show excellent application potentials.
通过氧还原反应（ORR）进行过氧化氢（H₂O₂）的分散式电合成可实现消毒控制、制浆和纺织品漂白、废水处理以及可再生能源存储等应用。过渡金属氧化物通常不是高效催化剂，因为它们对生成H₂O₂的选择性更高。在此，研究表明二价3d过渡金属阳离子（Mn、Fe、Co、Ni和Cu）可以控制铌铁矿纳米颗粒的催化活性和选择性。它们是通过水热法使用聚氧铌酸盐（K₄H₂Nb₆O₁₉·13H₂O）和二价金属阳离子合成的。在碱性电解质中，从0.2到0.6 V的宽电位窗口内，最佳的NiNb₂O₅具有96%的H₂O₂选择性以及相应92%的H₂O₂法拉第效率，优于其他过渡金属氧化物催化剂。非原位X射线光电子能谱和原位傅里叶变换红外光谱研究，以及密度泛函理论计算表明，3d过渡金属会移动催化活性表面Nb原子的d带中心，并改变它们与ORR中间体的相互作用。在应用演示中，NiNb₂O₅在H型电解槽中可实现高达1 mol g⁻¹ h⁻¹的H₂O₂生产率，并且可以产生含有300×10⁻³ m H₂O₂的阴极电解液，以有效分解几种有机染料。低成本的3d过渡金属介导的铌铁矿催化剂显示出优异的应用潜力。
