Dual‐laser pulse‐patterned α‐Co(OH)₂/rGO heterointerface for accelerated water oxidation and surface phase‐transition via in‐situ Raman spectroscopy

Abstract The dynamic surface reconstruction of electrodes is a legible sign to understand the deep phase‐transition mechanistic and electrocatalytic origin during the oxygen evolution reaction (OER). Herein, we report a dual‐laser pulse‐patterned heterointerface of α‐Co(OH)₂ and reduced graphene oxide (rGO) nanosheets via pulsed laser irradiation in liquid (PLIL) to accelerate OER kinetics. α‐Co(OH)₂ was formed from the OH⁻ ions generated during the PLIL of GO at neutral pH. Co²⁺ modulation in tetrahedral coordination sites benefits as an electrophilic surface for water oxidation. Few d‐vacancies in Co²⁺ increase its affinity toward oxygen, lowering the energy barrier and generating many CoOOH and CoO₂ active sites. rGO with an ordered π‐conjugated system aids the surface adsorption of OOH*, O*, and OH* during OER. α‐Co(OH)₂ surface phase‐transition and OER mechanistic steps occurred via phase‐reconstruction to CoOOH and CoO₂ reactive intermediates, uncovered using in situ electrochemical–Raman spectroscopy. Our findings in the dual‐laser pulse strategy and the surface reconstruction correlation in active OER catalysts pave the path for paramount in multiple energy technologies. image