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In this study, a series of molybdenum-doped ultrathin BiVO4 nanosheets (Mo-BVO) were successfully synthesized by a facile hydrothermal method. The results indicated that Mo-BVO nanosheets exhibited high photocatalytic efficiency of methyl blue (MB) degradation under visible-light irradiation. Particularly, 1% Mo-BVO exhibited an optimum photo-degradation rate of more than 97% within 60 min under visible-light illumination, which was approximately 3.8 times greater than that of pure BVO. The experimental characterizations and DFT calculations manifested that the ultrathin BVO nanosheets and Mo doping were beneficial to provide abundant active sites, suppress the photoinduced charge recombination and extend the absorption visible-light range, thus enhancing the photocatalytic performance toward MB degradation. Additionally, the photocatalytic reaction mechanism was proposed based on the reactive species trapping experiments. This study was expected to design a highly active photocatalyst for pollution decomposition by modulating the photocatalytic properties and electronic band structure. [ABSTRACT FROM AUTHOR]

The influences of a series of (N, Mo, W) monodoping and N-Mo(W) codoping on the electronic structures of sodium niobate have been systematically investigated by density functional theory (DFT) calculations with the hybrid B3LYP functional. The results indicated that some localized N 2 p states were formed above the top of valence band (VB) after N-doping. In the case of Mo(W)-doping, the position of VB shifted up, meanwhile, the hybridization of Nb 4 d and Mo 4 d(W 5 d) states moved the conduction band (CB) downward, leading to narrowing the band gap. As for N-Mo codoped NaNbO3, the localized Mo 4 d states were formed near the bottom of CB while the localized N 2 p states appeared above the top of VB. When N-W codoping, the W 5 d p states mixed with Nb 4 d states and then moved the top of CB downward as well as some localized N 2 p states were formed above the valence band (O 2 p), leading to the obvious reduction of the photon transition energy compared with that of NaNbO3. [ABSTRACT FROM AUTHOR]

Water electrolysis suffers from electron transfer barriers during oxygen evolution reactions, which are spin-related for magnetic materials. Here, the electron transfer at the Fe_{64}Ni_{36}-FeNiO_{x}H_{y} interface is effectively accelerated when the electrode is heated to trigger the Invar effect in Fe_{64}Ni_{36} Invar alloy, providing more unoccupied orbitals as electron transfer channels without pairing energy. As a result of thermally stimulated changes in electronic states, Fe_{64}Ni_{36}/FeNiO_{x}H_{y} achieved a cascaded oxidation of the catalytic center and water. Unlike direct modifications made by varying compositions and synthesis, regulating electronic states by energy field opens a new avenue to discover materials with energy coupling effects.

The sluggish electron transfer kinetics in electrode polarization driven oxygen evolution reaction (OER) result in big energy barriers of water electrolysis. Accelerating the electron transfer at the electrolyte/catalytic layer/catalyst bulk interfaces is an efficient way to improve electricity-to-hydrogen efficiency. Herein, the electron transfer at the Sr 3 Fe 2 O 7 @SrFeOOH bulk/catalytic layer interface is accelerated by heating to eliminate charge disproportionation from Fe 4+ to Fe 3+ and Fe 5+ in Sr 3 Fe 2 O 7 , a physical effect to thermally stabilize high-spin Fe 4+ (t 2g 3 e g 1 ), providing available orbitals as electron transfer channels without pairing energy. As a result of thermal-induced changes in electronic states via thermal comproportionation, a sudden increase in OER performances was achieved as heating to completely suppress charge disproportionation, breaking a linear Arrhenius relationship. The strategy of regulating electronic states by thermal field opens a broad avenue to overcome the electron transfer barriers in water splitting., Competing Interests: Competing interests statement:The authors declare no competing interest.