MXenes-like multilayered tungsten oxide architectures for efficient photoelectrochemical water splitting

Abstract Currently, the multilayer architecture is recognized as one of shining stars with exciting applications in environment and catalysis, energy storage/conversion, optoelectronics and so forth. However, different to the typical MXenes, the fabrication of layered transition metal oxides is still a grand challenge, since they are highly difficult to be exfoliated into multilayered structures, owing to their intrinsically strong covalent bond. Here, we report the controlled growth of MXenes-like WO3 architecture in the families of transition metal oxides with perfectly multilayered features, by tailoring the formation of precursor WO3·H2O based on the competition between the concentrations of WO42− and anions (NO3–, Cl−) within the solution. The as-built multilayer WO3 architecture has overall superior physical performance to conventional solid counterparts, and exhibits a remarkable photocurrent density of 2.3 mA cm−2 at 1.23 vs. RHE under AM 1.5G illumination, which is the highest one among those of WO3 photoanodes without cocatalysts/dopants in neutral solution ever reported.