Instant formation of excellent oxygen evolution catalyst film via controlled spray pyrolysis for electrocatalytic and photoelectrochemical water splitting

The retarded kinetics of oxygen evolution on electrodes is a bottleneck for electrochemical energy conversion and storage systems.NiFe-based electrocatalysts provide a cost-effective choice to confront this challenge.However,there is a lack of facile techniques for depositing compact catalytic films of high coverage and possessing a state-of-the-art performance,which is especially desired in photoelectrochemical(PEC)systems.Herein,we demonstrate a spray pyrolysis(SP)route to address this issue,featuring the kinetic selective preparation towards the desired catalytic-active material.Differing from reported SP protocols which only produce inactive oxides,this approach directly generates a unique composite film consisting of NiFe layered oxyhydroxides and amorphous oxides,exhibiting an overpotential as small as 255 mV(10 mA cm^(−2))and a turnover frequency of∼0.4 s^(−1)per metal atom.By using such a facile protocol,the surface rate-limiting issue of BiVO_(4)photoanodes can be effectively resolved,resulting in a charge injection efficiency of over 90%.Considering this deposition directly start from simple nitrates but only takes several seconds to complete,we believe it can be developed as a widely applicable and welcomed functionalization technique for diverse electrochemical devices.