変動電圧に強い酸化マンガン水電解触媒の開発～揺らぎの大きい自然エネルギーを用いた水素製造に貢献～

2025-10-20 理化学研究所

自己修復経路を導入した水電解触媒

＜関連情報＞

• https://www.riken.jp/press/2025/20251020_3/index.html
• https://www.nature.com/articles/s41893-025-01665-y

電圧変動に耐性のある酸素発生電気触媒 Oxygen evolution electrocatalysis resilient to voltage fluctuations

Ailong Li,Hideshi Ooka,Shuang Kong,Kiyohiro Adachi,Yuchen Zhang,Kazuna Fushimi,Satoru Hamamoto,Masaki Oura,Sun Hee Kim,Daisuke Hashizume & Ryuhei Nakamura
Nature Sustainability  Published:20 October 2025
DOI:https://doi.org/10.1038/s41893-025-01665-y

Abstract

Renewable energy sources, such as solar and wind power, fluctuate on timescales of seconds to hours. Harnessing such intermittent energy to drive chemical synthesis represents a major challenge, as conventional 3d-block metal catalysts are prone to degradation even under small variations in operating potential. Here we report an electrochemical oxygen evolution reaction system that is tolerant to voltage fluctuations through the design of catalytic pathways. By leveraging the redox chemistry of manganese oxide, we integrated the Guyard reaction (4Mn²⁺ + Mn⁷⁺ → 5Mn³⁺) as a regeneration pathway into the catalytic cycle. Unlike other 3d-block metal catalysts, which rapidly degrade under fluctuating conditions, the constructed manganese oxide system shows resilience to voltage fluctuations by alternating between decomposition and regeneration. When the voltage is switched between 1.68 and 3.00 V repeatedly, the catalyst can maintain an oxygen evolution reaction at pH 2 for more than 2,000 h, highlighting the importance of pathway design for sustainable energy conversion from intermittent renewable sources.