Abdullah Muhammad Imran, Hameed Asima, Zhang Ning, Islam Md Hujjatul, Ma Mingming, Pollet Bruno G
CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
Department of Biology and Environmental Engineering, Hefei University, Hefei, Anhui 230022, China.
ACS Appl Mater Interfaces. 2021 Jul 7;13(26):30603-30613. doi: 10.1021/acsami.1c06258. Epub 2021 Jun 25.
Most of the current electrocatalysts for the methanol oxidation reaction are precious group metals such as Pt, Pd, and Ru. However, their use is limited due to their high cost, scarcity, and issues with carbon monoxide poisoning. We developed a simple method to prepare a nickel foam (NF)-based monolith electrode with a NiO nanosheet array structure as an efficient electrocatalyst toward the oxidation of methanol to produce formate. By a simple ultrasonic acid treatment and air oxidation at room temperature, an inert NF was converted to NiO/NF as a catalytically active electrode due to the uniform NiO nanosheet array that was rapidly formed on the surface of NiO/NF. In alkaline electrolytes containing methanol, the as-prepared NiO/NF catalysts exhibited a lower methanol oxidation reaction (MOR) potential of +1.53 V RHE at 100 mA cm compared to that of inert NF samples. The difference in potentials between the and the at that current density was found to be 280 mV, indicating that methanol oxidation occurred at lower potentials as compared to the oxygen evolution reaction (OER). We also observed that the NiO/NF could also efficiently catalyze the oxidation of CO without being poisoned by it. NiO/NF retained close to 100% of its initial activity after 20,000 s of methanol oxidation tests at high current densities above 200 mA cm. Because of the simple synthesis method and the enhanced catalytic performance and stability of NiO/NF, this allows methanol to be used as an OER masking agent for the energy-efficient generation of value-added products such as formic acid and hydrogen.
目前用于甲醇氧化反应的大多数电催化剂是铂、钯和钌等贵金属。然而，由于其高成本、稀缺性以及一氧化碳中毒问题，它们的应用受到限制。我们开发了一种简单的方法来制备具有NiO纳米片阵列结构的泡沫镍（NF）基整体电极，作为将甲醇氧化生成甲酸盐的高效电催化剂。通过简单的超声酸处理和室温空气氧化，惰性NF转化为NiO/NF作为催化活性电极，这是由于在NiO/NF表面迅速形成了均匀的NiO纳米片阵列。在含有甲醇的碱性电解质中，与惰性NF样品相比，所制备的NiO/NF催化剂在100 mA cm²时表现出更低的甲醇氧化反应（MOR）电位，为+1.53 V（相对于可逆氢电极，RHE）。在该电流密度下，甲醇氧化反应电位与析氧反应（OER）电位之间的差值为280 mV，这表明与析氧反应相比，甲醇氧化在更低的电位下发生。我们还观察到，NiO/NF也能有效催化CO的氧化，且不会被其毒化。在高于200 mA cm²的高电流密度下进行20000 s的甲醇氧化测试后，NiO/NF仍保持接近100%的初始活性。由于合成方法简单以及NiO/NF具有增强的催化性能和稳定性，这使得甲醇能够用作OER掩蔽剂，以高效生成甲酸和氢气等增值产品。
