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The oxygen evolution reaction (OER) is a key process involved in energy and environment‐related technologies. An ideal OER electrocatalyst should show high exposure of active sites and optimal adsorption energies of oxygenated species. However, earth‐abundant transition‐metal‐based OER electrocatalysts still operate with sluggish OER kinetics. Here, a cation‐exchange route is reported to fabricate cobalt‐vanadium‐iron (oxy)hydroxide (CoV‐Fe0.28) nanosheets with tunable binding energies for the oxygenated intermediates. The formation of an amorphous/crystalline heterostructure in the CoV‐Fe0.28 catalyst boosts the exposure of active sites compared to their crystalline and amorphous counterparts. Furthermore, the synergetic interaction of Co, V, and Fe cations in the CoV‐Fe0.28 catalyst subtly regulates the local coordination environment and electronic structure, resulting in the optimal thermodynamic barrier for this elementary reaction step. As a result, the CoV‐Fe0.28 catalyst exhibits superior electrocatalytic activity toward the OER. A low overpotential of 215 mV is required to afford a current density of 10 mA cm−2 with a small Tafel slope of 39.1 mV dec−1, which outperforms commercial RuO2 (321 mV and 86.2 mV dec−1, respectively). [ABSTRACT FROM AUTHOR]

Hydrogen fuel is considered as one of the most clean renewable resources, warranting it a primary alternative to fossil fuels for future energy supplies. Electrocatalytic water splitting is an eco‐friendly technique for high‐purity hydrogen production. However, the sluggish dynamics of its two half‐reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), are tough challenges impeding the practical application of this technology. In these years, external field‐assisted HER and OER have attracted extensive research interests. Herein, the effects of various fields, including electric field, magnetic field, strain, and light, on electrocatalytic HER and OER are systematically discussed. The focus is how to integrate the external fields with the electrocatalytic systems and the fundamentals of field promoted HER/OER activities. In the end, the key challenges facing this rapidly progressing research field are highlighted and possible strategies addressing them are indicated. [ABSTRACT FROM AUTHOR]

The replacement of expensive noble-metals cocatalysts with inexpensive, earth-abundant, metallic nonmetal materials in most semiconductor-based photocatalytic systems is highly desirable. Herein, we report the fabrication of stable 1T-MoS2 slabs in situ grown on CdS nanorods (namely, 1T-MoS2@CdS) by using a solvothermal method. As demonstrated by ultrafast transient absorption spectroscopy, in combination with steady-state and time-resolved photoluminescence, the synergistic effects resulting from formation of the intimate nanojunction between the interfaces and effective electron transport in the metallic phase of 1T-MoS2 largely contribute to boosting the photocatalytic activity of CdS. Notably, the heterostructure with an optimum loading of 0.2 wt % 1T-MoS2 exhibits an almost 39-fold enhancement in the photocatalytic activity relative to that exhibited by bare CdS. This work represents a step towards the in situ realization of a 1T-phase MoS2-based heterostructure as a promising cocatalyst with high performance and low cost. [ABSTRACT FROM AUTHOR]

The schemes of the corresponding "electrons accepting effect" and "hydrophilic effect" of TiO 2 -CA, TiO 2 -PA, and TiO 2 -EG compared with TiO 2. [Display omitted] • The carbonyl group (–C=O) in TiO 2 -CA possess a stronger reducing capability and act as an "electrons acceptor" • The only alcohol-hydroxyl group (–OH) in TiO 2 -CA can decrease the mass transfer resistance and serve as a "super hydrophilic absorber". • The TiO 2 -CA sample with dual functional groups (–C=O and alcohol-(–OH)) show significantly synergistic enhanced photocatalytic H 2 -evolution activity. Photocatalytic H 2 evolution from water splitting in liquid–solid two-phase requires an efficient photocatalyst with excellent ability of charge separation and reactant molecular diffusion. In this study, the super hydrophilic-electrons acceptor with abundant –C=O and –OH functional groups were evenly grafted onto rutile TiO 2 nanorods surface to speed up the charge separation and water molecular diffusion, respectively. The photocatalytic results showed that the TiO 2 -CA grafted by citric acid (with three –C=O, three carboxy-(–OH) and one alcohol-(–OH)) presented a 1.48° contact angle and a distinct increased H 2 -production activity (48.5 mmol·h−1·g−1), whereas the TiO 2 -PA grafted by propane-1,2,3-tricarboxylic acid (Just lack of one alcohol-(–OH) compared with TiO 2 -CA) showed a 30.95° contact angle and a decreased H 2 -production activity (19.3 mmol·h−1·g−1) compared to the unmodified TiO 2 (25.8 mmol·h−1·g−1), indicating that the super hydrophilic-electrons acceptor is vitally important to the photocatalytic activity of TiO 2. Based on the present results, the carbonyl group (–C=O) possess a stronger reducing capability and act as "electrons acceptor", while the only alcohol-hydroxyl group (–OH) in TiO 2 -CA can decrease the mass transfer resistance and serve as "super hydrophilic absorber". Considering its mild preparation, inexpensive cost, and admirable efficiency, the super hydrophilic-electrons acceptor with dual functional groups regulated TiO 2 can become a promising way for potential application in photocatalytic field. [ABSTRACT FROM AUTHOR]

The porous nitrogen-rich g-C 3 N 4 nanotubes are synthesized by a supramolecular assembly method, which exhibit excellent CO 2 reduction performance, and the performance is higher than most reported g-C 3 N 4 -based photocatalysts. In addition, the porous nitrogen-rich g-C 3 N 4 nanotubes have broad applications in Photocatalytic CO 2 reduction and photocatalytic hydrogen evolution. • The porous nitrogen-rich g-C 3 N 4 nanotubes are synthesized by self-assembled approach. • The 1D tubular structure and abundant NH 2 groups can promote the CO 2 photoreduction reaction. • The porous nitrogen-rich g-C 3 N 4 nanotubes show excellent visible light-driven CO 2 reduction performance. • This finding provides a successful paradigm for the synthesis of functional groups-doped g-C 3 N 4 with a unique structure. The conversion of carbon dioxide (CO 2) into fuels and valuable chemicals using solar energy is a promising method for reducing CO 2 emissions and solving energy supply issues. However, the development of inexpensive, efficient and metal-free materials for photocatalytic CO 2 reduction is challenging. Herein, we report a facile supramolecular self-assembly strategy for the preparation of porous nitrogen-rich graphitic carbon nitride (g-C 3 N 4) nanotubes with Lewis basicity and a large surface area, which are beneficial for the adsorption of CO 2 and, consequently, the enhancement of the photocatalytic CO 2 reduction activity. The metal-free porous nitrogen-rich g-C 3 N 4 nanotubes catalyst exhibits a superior visible-light-induced CO 2 -to-CO conversion rate of 103.6 μmol g−1 h−1, which is 17 and 15 times higher than those of bulk g-C 3 N 4 (6.1 μmol g−1 h−1) and P25-TiO 2 (7.1 μmol g−1 h−1), respectively, and exceeds the performance of most metal-free photocatalysts. This work provides new insights into the synthesis of functional groups-modified g-C 3 N 4 with a unique structure for effective photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]