One-pot corrosive synthesis of Ru-Fe3O4 heterostructure: A localized photothermal electrocatalyst towards accelerated water splitting

Photothermal effect localized on the electrode surface has been introduced into water splitting electrocatalysis to achieve energy-efficient hydrogen production, which is attractive for industrial water electrolysis. However, the lack of efficient photothermal electrocatalysts for overall water splitting hinders its widespread application. Herein, we report a novel photothermal-electrocatalytic system of Ru-Fe3O4 heterojunctions grown on iron foam (Ru-Fe3O4/IF). Through a feasible hydrothermal corrosion strategy, ruthenium ions effectively etch the reactive IF substrate to form Ru-Fe3O4 heterojunctions. The Ru-Fe3O4/IF enables remarkable photothermal conversion under near infrared (NIR) light irradiation due to the contributions of Fe3O4 and metallic Ru nanoparticles. When exposed to NIR light irradiation, the photothermal Ru-Fe3O4/IF shows small overpotentials (η10) of 297 and 128 mV for oxygen and hydrogen evolution reactions, respectively, which are 58 and 45 mV lower than those without NIR light irradiation and compare favorably to most of previously reported photothermal electrocatalysts. Importantly, the photothermal Ru-Fe3O4/IF exhibits a low cell voltage of 1.521 V at 10 mA cm−2 with good durability within 24 h. This study provides a new platform for improving water splitting electrocatalysis by utilizing the photothermal effect.