In this work, a two-dimensional porous structure of a V-doped NiO film with excellent electrochromic properties on an ITO substrate was synthesized by a hydrothermal method. The influence of V5+ ions on the NiO film was explored by adjusting the amount of V doping, including refining the crystal grains, increasing the specific surface area of the film, and accelerating the diffusion rate of OH– in the film. Compared with the undoped NiO film, a 3 atom % V-doped NiO film comes out with superior electrochromic properties with large optical transmittance modulation (81.9% at 600 nm), fast response times (1.2 and 0.9 s), and excellent cycle stability (90.6%). This work creates innovation direction in the field of intelligent energy-saving window materials with high electrochromic properties.

By combining the advantages of doping to change the electronic structure of molybdenum disulfide (MoS 2 ), transition metal phosphides, and MXene, we proposed the idea of designing and preparing a new type of composite material, P-doped MoS 2 /Ni 2 P/Ti 3 C 2 T x heterostructures (denoted as P@MNTC), to serve as the hydrogen evolution reaction (HER) catalyst of electrochemical water splitting. The as-prepared P@MNTC heterostructures show a significant HER activity with an overpotential of 120 mV at 10 mA cm -2 in alkaline electrolyte, with decreasing 105 and 125 mV compared with those of MoS 2 and MXene, respectively. The density functional theory indicates that the P doping and synergy effect of Ti 3 C 2 T x can enhance the activation of MoS 2 and thus promote dissociation and absorption of H 2 O during HER process. This strategy provides a promising way to develop high-efficiency MoS 2 -and Ti 3 C 2 T x -based composite catalysts for alkaline HER.