Design and Application of a High-Surface-Area Mesoporous δ-MnO<sub>2</sub> Electrocatalyst for Biomass Oxidative Valorization
作者:Changlong Wang、Hans-Josef Bongard、Claudia Weidenthaler、Yufeng Wu、Ferdi Schüth
DOI:10.1021/acs.chemmater.1c04223
日期:2022.4.12
The design and application of electrocatalysts based on Earth-abundant transition-metal oxides for biomass valorization remain relatively underexplored. Here, we report a nanocasting route to synthesize mesoporous δ-MnO2 with a high surface area (198 m2/g), high pore volume, and narrow pore size distributions to address this issue. By taking structural advantages of mesoporous oxides, this mesoporous δ-MnO2 is employed as a highly efficient, selective, and robust anode for 5-hydroxymethylfurfural (HMF) electrochemical oxidation to 2,5-furandicarboxylic acid (FDCA) with a high yield (98%) and faradic efficiency (98%) under alkaline conditions. The electrocatalyst is also effective for the more difficult HMF electro-oxidation under acidic conditions, forming both FDCA and maleic acid as value-added products in a potential-dependent manner. Experimental results combined with theoretical calculations provide insights into the reaction kinetics and the reaction pathways of electrochemical HMF oxidation over this advanced electrocatalyst. This work thus showcases the rational design of non-noble metal electrodes for multiple applications, such as oxygen evolution, water electrolysis, and biomass upgrading with high energy efficiency.
基于地球丰富的过渡金属氧化物用于生物质增值的电催化剂的设计和应用仍然相对不充分。在这里,我们报告了一种纳米铸造方法,用于合成具有高比表面积(198 m2/g)、高孔容和窄孔径分布的中孔δ-MnO2,以解决这一问题。通过利用中孔氧化物的结构优势,这种中孔δ-MnO2被用作5-羟甲基糠醛(HMF)电化学氧化为2,5-呋喃二甲酸(FDCA)的高效、选择性和坚固的阳极,在碱性条件下具有高产率(98%)和法拉第效率(98%)。该电催化剂在酸性条件下对更困难的HMF电氧化也有效,以电位依赖的方式形成FDCA和马来酸作为增值产品。实验结果与理论计算相结合,为这种先进电催化剂的电化学HMF氧化反应的动力学和反应途径提供了见解。因此,这项工作展示了非贵金属电极的合理设计,可用于多种应用,如高能效的氧析出、水电解和生物质升级。