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The synthesis and characterization of an indium-substituted quaternary heteropoly acid with a Keggin structure, H4[In(H2O)PW9Mo2O39]·11H2O (PMo9W2In), is reported. At 18 °C under 80% relative humidity, PMo9W2In displays protonic conductivity of 2.32 × 10−4 S cm−1 with an activation energy of 35.52 kJ mol−1, indicating that it is a potential solid protonic conductor following the vehicle mechanism. Its conductivity increases with temperature in the measured temperature range. [ABSTRACT FROM AUTHOR]

P2W16Mo2/PVA/TiO2 composite films were prepared by doping TiO2 nanoparticles (P25) into P2W16Mo2/PVA. Irradiated with UV light, composite films changed from light yellow to blue. P2W16Mo2/PVA and P2W16Mo2/PVA/TiO2 composite films (before and after UV irradiation) were characterized by IR spectroscopy, which verified that the basic structure of H6P2W16Mo2O62 and PVA were not destroyed in the composite films. The photochromism performance of P2W16Mo2/PVA and P2W16Mo2/PVA/TiO2 composite films were explored by UV–vis absorption spectra. Compared with P2W16Mo2/PVA composite films, photochromism response time of composite films doped in TiO2 was more sensitive and the UV–vis adsorption spectra absorbance increased significantly. With time, P2W16Mo2/PVA/TiO2 composite films had a circulation ability of rising-fading color. The composition of the composite film with the best photochromism performance was obtained. [ABSTRACT FROM AUTHOR]

Spiro‐OMeTAD is currently the most widely used hole transport material for the preparation of high‐performance perovskite solar cells (PSCs), usually requiring the addition of additives to achieve the desired electronic conductivity. However, the quality of the film is degraded owing to the addition of additives. Holes and defects can be observed, and the dispersion of the additives are uneven inside. Here, a copper coordination polymer, Cu‐bix, with matching energy level and fluorescent properties was screened for use as an additional additive to dope Spiro‐OMeTAD. The doping of Cu‐bix effectively improved the dispersion state of the additives in the hole transport layers and alleviated the aggregation of LiTFSI (lithium bis(trifluoromethanesulfonyl)imide) or/and lithium salt complexes in the film. Owing to better dispersion of the additives, Spiro‐OMeTAD was more fully and uniformly oxidized whereas the possibility of charge recombination was reduced in the devices. Furthermore, the flat and tightly bonded film layer obtained by optimization of the doping amount can efficiently transfer holes from the perovskite layers to the hole transport layers. Possible interaction mechanisms between additives and the copper coordination polymer are proposed and discussed. The resulting power conversion efficiency (PCE) for Cu‐bix‐doped PSCs was improved from 16.52 % to 18.47 % compared to the pristine devices, and this type of PSCs also showed a long stability in air owing to the increased hydrophobicity of the Cu‐bix‐based hole transport layers. [ABSTRACT FROM AUTHOR]

MXenes and doped carbon nanotubes (CNTs) have entered into research arenas for high‐rate energy storage and conversion. Herein, a method of postsynthesis of MXenes in boron, nitrogen codoped CNTs (BNCNTs) is reported with their electrocatalytical hydrogen evolution performance. The encapsulation of hexagonal molybdenum nitrate nanoparticles (h‐MoN NPs) into BNCNTs protects h‐MoN NPs from agglomeration and poisoning in the complex environment. In principle, the synergism of B and N dopants on the doped CNTs and confined h‐MoN NPs produces extremely active sites for electrochemical hydrogen evolution. Density functional theory calculations reveal that the active sites for hydrogen evolution originate from the synergistic effect of h‐MoN(001)/CN (graphitic N doping) and h‐MoN(001)/BNC. The h‐MoN@BNCNT electrocatalyst exhibits a small overpotential of 78 mV at 10 mA cm−2 and Tafel slope of 46 mV per decade, which are dramatically improved over all reported MoN‐based materials and doped CNTs. Additionally, it also exhibits outstanding electrochemical stability in environments with various pH values and seawater media from South China Sea.Nanoflakes of hexagonal molybdenum nitrate are synthesized in the matrix of boron, nitrogen codoped carbon nanotubes with efficient electrocatalytic hydrogen evolution performance in acidic, neutral, and alkaline solutions. Electrolysis of seawater can also be operated by using as‐obtained catalysts because doped carbon nanotubes can protect hexagonal molybdenum nitrate from agglomeration and poisoning in the complex environment. [ABSTRACT FROM AUTHOR]