Temperature Dependence of Electrocatalytic and Photocatalytic Oxygen Evolution Reaction Rates Using NiFe Oxide

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• 作者：Ela Nurlaela ; Tatsuya Shinagawa ; Muhammad Qureshi ; Dattatray S. Dhawale ; Kazuhiro Takanabe
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：March 4, 2016
• 年：2016
• 卷：6
• 期：3
• 页码：1713-1722
• 全文大小：489K
• ISSN：2155-5435

文摘

The present work compares the oxygen evolution reaction (OER) in electrocatalysis and photocatalysis in aqueous solutions using nanostructured NiFeO_x as catalysts. The impacts of pH and reaction temperature on the electrocatalytic and photocatalytic OER kinetics were investigated. For electrocatalysis, a NiFeO_x catalyst was hydrothermally decorated on Ni foam. In 1 M KOH solution, the NiFeO_x electrocatalyst achieved 10 mA cm^–2 at an overpotential of 260 mV. The same catalyst was decorated on the surface of Ta₃N₅ photocatalyst powder. The reaction was conducted in the presence of 0.1 M Na₂S₂O₈ as a strong electron scavenger, thus likely leading to the OER being kinetically relevant. When compared with the bare Ta₃N₅, NiFeO_x/Ta₃N₅ demonstrated a 5-fold improvement in photocatalytic activity in the OER under visible light irradiation, achieving a quantum efficiency of 24% at 480 nm. Under the conditions investigated, a strong correlation between the electrocatalytic and photocatalytic performances was identified: an improvement in electrocatalysis corresponded with an improvement in photocatalysis without altering the identity of the materials. The rate change at different pH was likely associated with electrocatalytic kinetics that accordingly influenced the photocatalytic rates. The sensitivity of the reaction rates with respect to the reaction temperature resulted in an apparent activation energy of 25 kJ mol^–1 in electrocatalysis, whereas the apparent activation energy in photocatalysis was 16 kJ mol^–1. The origin of the difference in these activation energy values is likely attributed to the possible effects of temperature on the individual thermodynamic and kinetic parameters of the reaction process. The work described herein demonstrates a method of “transferring the knowledge of electrocatalysis to photocatalysis” as a strong tool to rationally and quantitatively understand the complex reaction schemes involved in photocatalytic reactions.