Light-induced quantum reconfiguration of oxyhydroxides for photoanodes with 4.24% efficiency and stability beyond 250 hours

Photoelectrochemical (PEC) water splitting is attracting significant research interest in addressing sustainable development goals in renewable energy for the future. Current state-of-the-art, however, cannot provide photoanodes with simultaneously high efficiency and long-lasting device lifetime. Here, we report a large-scale NiFe oxyhydroxides-alloy hybridized cocatalyst layer on photoanodes that exhibit a record value of applied bias photon-to-current efficiency (ABPE) of 4.24% in buried homojunction-free photoanodes and stability over 250 hours with above 88% retention of the initial current density. These performances represent an increase over the present highest-performing technology by 408% in stability and the most stable competitor by over 330% in efficiency in alkaline media. These results originate from a previously unexplored mechanism of light-induced atomic reconfiguration and surface amorphization in NiFe-based materials. This process self-generates at low biases and, in short times, a catalytic-protective amorphous/crystalline heterostructure that provides abundant highly catalytic active sites for reaction and insulates the photoanode from performance degradation. NiFe oxyhydroxides generated by photons are more than 200% higher than the quantity that pure electrocatalysis would otherwise induce, overcoming the threshold for an efficient oxygen reduction reaction in the device. While of immediate interest in the industry of water splitting, the light-induced NiFe oxyhydroxides-alloy co-catalyst developed in this work provides a general strategy to enhance further the performances and stability of PEC devices for a vast panorama of chemical reactions, ranging from biomass valorization to organic waste degradation, and CO2-to-fuel conversion.