To improve photoelectrochemical (PEC) activity of hematite, the modification of energy band by doping 3d transition metal ions Cu and Ti into α-Fe2O3 were studied via the first-principles calculations with density function theory (DFT)+U method. The results show that the band gap of hematite is ∼2.1 eV and n-type dopant Ti improves the electric conductivity, confirmed by recent experiments. The p-type dopant Cu enhances the utilization ratio of solar energy, shifts both valance, and conduction band edges to a higher energy level, satisfying hydrogen production in the visible light driven PEC water splitting without voltage bias.

Two-dimensional (2D) Co-based MOF-on-MOF heterojunction nanostructures with improved electrocatalytic activity were successfully constructed via a mild two-step solution route, employing Co2+ ions as the center atoms, and 1,4-benzenedicarboxylate (BDC) and 4,4′-biphenyldicarboxylate (BPDC) as ligands. The as-obtained heterojunction nanostructures were characterized by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) technologies. Electrochemical measurements showed that as-prepared Co-BPDC/Co-BDC heterojunction nanostructures presented markedly enhanced OER electrocatalytic activity, compared with single Co-BPDC, Co-BDC, and/or their physical mixture. Also, the Co-BPDC/Co-BDC-3 heterojunction prepared after treatment for 3 h exhibited the strongest catalytic activity. To reach the current density j geo = 10 mA cm–2, the Co-BPDC/Co-BDC-3 heterojunction-modified glassy carbon electrode required an overpotential of 335 mV in 1 M KOH, which was reduced by 57 and 93 mV, compared to the electrodes modified by Co-BDC and Co-BPDC, respectively. Simultaneously, the heterojunction catalyst also displayed better long-term stability. The improvement of the above performances should be attributed to the increased structure stability, BET surface area, ECSA, and electron transfer ability of the heterojunction.

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The electrocatalytic synthesis of low-density polyethylene (LDPE) from carbon dioxide on a nanostructured (ns)TiO2 film electrode was investigated by controlled potential electrolysis in a solvent mixture of water and the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMI]BF4) at room temperature under ambient pressure. Under these conditions, the nsTiO2 film is remarkably efficient and selective for the electroreduction of CO2. The current efficiency for the formation of the electrolytic product is about 8-14% at -1.50 V (vs SCE). The electrocatalytic activity of the electrode in the electrochemical reduction of CO2 was investigated by cyclic voltammetry (CV), and the probable electrode reaction mechanism is discussed.

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Fe-doped Co-Mo-S microtubes were successfully synthesized through a multistep synthetic route, employing MoO3 microrods as the sacrificial template, Co(NO3)2•6H2O and Fe(SO4)2∙7H2O as the metal sources, 2-Methylimidazole (2-MI) as the ligand...