Operando unraveling photothermal-promoted dynamic active-sites generation in NiFe 2 O 4 for markedly enhanced oxygen evolution

Significance As the electrochemical reconstruction into highly active species is anticipated to arise under the oxidative conditions, activating and tailoring the surface reconstruction via a rational and effective strategy is pivotal to improve the oxygen evolution reaction (OER) activity. In this work, we advance a robust process, that is, the photothermal effect originated from the spinel NiFe 2 O 4 catalyst, to render its dynamic transition into active (Ni,Fe)oxyhydroxides species that triggers highly efficient oxygen evolution. Significantly, the reaction kinetics of OER are improved due to the lowered activation energy, as modulated by the photothermal energy-promoted surface reconstruction. More importantly, the operando Raman spectroelectrochemistry study and first-principle calculation collectively unveil the mechanism of photothermal-assisted enhancement in OER reaction.