ABSTRACT
We adopted a simple one-step electrochemical deposition to acquire an efficient nickel cobalt phosphorus (NiCoP) catalyst, which avoided the high temperature phosphatization engineering involved in the traditional synthesis method. The effects of electrolyte composition and deposition time on electrocatalytic performance were studied systematically. The as-prepared NiCoP achieved the lowest overpotential (η10 = 111 mV in the acidic condition and η10 = 120 mV in the alkaline condition) for the hydrogen evolution reaction (HER). Under 1 M KOH conditions, optimal oxygen evolution reaction (OER) activity (η10 = 276 mV) was also observed. Furthermore, the bifunctional NiCoP catalyst enabled a high-efficiency overall water-splitting by applying an external potential of 1.69 V. The surface valence and structural evolution of NiCoP samples with slowly decaying stability under alkaline conditions are revealed by XPS. The NiCoP is reconstructed into the Ni(Co)(OH)2 (for HER) and Ni(Co)OOH (for OER) on the surface with P element loss, acting as real "active sites".
ABSTRACT
Recently, passive solar-driven interfacial evaporation has become one of the fastest-growing technologies for solar energy utilization and desalination. Herein this patent, we provide an overview of other emerging and potential applications of evaporation nanosystems beyond desalination, i.e., electricity generation, organics rejection, and sterilization. These extended functions can be a benefit for energy and environmental issues.
ABSTRACT
MAX phases are frequently dominated as precursors for the preparation of the star material MXene, but less eye-dazzling by their own potential applications. In this work, the electrocatalytic hydrogen evolution reaction (HER) activity of MAX phase is investigated. The MAX-derived electrocatalysts are prepared by a two-step in situ electrosynthesis process, an electrochemical etching step followed by an electrochemical deposition step. First, a Mo2 TiAlC2 MAX phase is electrochemically etched in 0.5 m H2 SO4 electrolyte. Just several hours, electrochemical dealloy etching of Mo2 TiAlC2 MAX powders by applying anode current can acquire a moderated HER performance, outperforming most of reported pure MXene. It is speculated that in situ superficially architecting endogenous MAX/amorphous carbide (MAC) improves its intrinsic catalytic activity. Subsequently, highly active metallic Pt nanoparticles immobilized on MAC (MAC@Pt) shows a transcendental overpotential of 40 mV versus RHE in 0.5 m H2 SO4 and 79 mV in 1.0 m KOH at the current density of 10 mA cm-2 without iR correction. Ultrahigh mass activity of MAC@Pt (1.5 A mgpt -1 ) at 100 mV overpotential is also achieved, 29-folds than those of commercial PtC catalysts.
