Recent advances of transition‐metal metaphosphates for efficient electrocatalytic water splitting

Abstract Sustainable production of H₂ through electrochemical water splitting is of great importance in the foreseeable future. Transition‐metal metaphosphates (TMMPs) have a three‐dimensional (3D) open‐framework structure and a high content of P (which exists as PO₃⁻), and therefore have been recognized as highly efficient catalysts for oxygen evolution reaction (OER) and the bottleneck of electrochemical water splitting. Furthermore, TMMPs can also contribute to hydrogen evolution reaction (HER) in alkaline and neutral media by facilitating water dissociation, and thus, overall water splitting can be achieved using this kind of material. In this timely review, we summarize the recent advances in the synthesis of TMMPs and their applications in OER and HER. We present a brief introduction of the structure and synthetic strategies of TMMPs in the first two parts. Then, we review the latest progress made in research on TMMPs as OER, HER, and overall water‐splitting electrocatalysts. In this part, the intrinsic activity of TMMPs as well as the current strategy for improving the catalytic activity will be discussed systematically. Finally, we present the future opportunities and the remaining challenges for the application of TMMPs in the electrocatalysis field.