Rapid Search for Electrochemical Reduction Conditions of Direct Liquid Injection Chemical Vapor Deposition Hematite...

A custom scanning electrochemical cell microscopy (SECCM) platform is built to rapidly search for electrochemical reduction conditions of a hematite thin film, which is prepared by direct liquid injection chemical vapor deposition (DLI-CVD), for enhanced photoelectrochemical (PEC) water splitting. An array of hematite spots is created under various SECCM reduction potentials and time lengths, followed by subsequent screening with the same SECCM probe under PEC conditions to identify the optimum reduction conditions. For example, the SECCM study shows that 6.5% reduction of a 128 nm hematite film shows the optimal PEC performance. This reduction condition obtained with SECCM can be extended to a bulk film to resemble the enhanced PEC activities. A Machine Learning model is built based on the quality data obtained with SECCM to guide the experimental efforts of searching for an efficient photoelectrode for PEC water splitting.