Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary T2N 1N4, Canada.
J Am Chem Soc. 2013 Aug 7;135(31):11580-6. doi: 10.1021/ja403102j. Epub 2013 Jul 24.
Photochemical metal-organic deposition (PMOD) was used to prepare amorphous metal oxide films containing specific concentrations of iron, cobalt, and nickel to study how metal composition affects heterogeneous electrocatalytic water oxidation. Characterization of the films by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed excellent stoichiometric control of each of the 21 complex metal oxide films investigated. In studying the electrochemical oxidation of water catalyzed by the respective films, it was found that small concentrations of iron produced a significant improvement in Tafel slopes and that cobalt or nickel were critical in lowering the voltage at which catalysis commences. The best catalytic parameters of the series were obtained for the film of composition a-Fe20Ni80. An extrapolation of the electrochemical and XPS data indicates the optimal behavior of this binary film to be a manifestation of iron stabilizing nickel in a higher oxidation level. This work represents the first mechanistic study of amorphous phases of binary and ternary metal oxides for use as water oxidation catalysts, and provides the foundation for the broad exploration of other mixed-metal oxide combinations.
光化学金属有机沉积（PMOD）被用于制备含有特定浓度铁、钴和镍的非晶态金属氧化物薄膜，以研究金属组成如何影响多相电催化水氧化。通过能量色散 X 射线光谱和 X 射线光电子能谱对薄膜进行的表征证实了所研究的 21 种复杂金属氧化物薄膜中每一种都具有极好的化学计量控制。在研究各自薄膜催化的水电化学氧化时，发现少量的铁可以显著改善塔菲尔斜率，而钴或镍则对降低催化起始电压至关重要。该系列中最佳的催化参数是组成 a-Fe20Ni80 的薄膜。电化学和 XPS 数据的外推表明，这种二元薄膜的最佳性能是铁将镍稳定在更高的氧化态的表现。这项工作代表了首次对用于水氧化催化剂的二元和三元金属氧化物非晶相进行的机理研究，为广泛探索其他混合金属氧化物组合奠定了基础。
