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Herein, V-doped cobalt hydroxides grown on carbon cloth (V-Co(OH)2/CC) were prepared via hydrothermal method. The incorporation of V can trigger phase transition and tune the local electronic structure of Co(OH)2, thereby improving the intrinsic alkaline HER activity. We find that the V-Co(OH)2 dominated by β-Co(OH)2 exhibits excellent HER activity with only 83 mV overpotential at a current density of 10 mA cm−2, which outperforms most reported hydroxide-based catalysts and even surpasses the commercial Pt/C at large current density (>160 mA cm−2). [ABSTRACT FROM AUTHOR]

MOF-5 has been criticized for its poor water stability, which results in complete damage of its traditional functionality. Therefore, there are very few researches about the further application of hydrolyzed MOF-5 (h-M). However, in this work, the h-M can function as both superior support and semiconductor for photocatalytic reaction after a water-based process. Herein, a rational design of Zn 0.2 Cd 0.8 S@h-MOF-5 (ZCS@h-M) heterojunction photocatalyst has been synthesized via a hydrothermal method with different mass ratio of ZCS. As demonstrated in the results of SEM and TEM, during the hydrothermal process, MOF-5 exfoliated into two-dimensional small sheets and ZCS nanoparticles embedded into h-M frameworks, which is in favor for the dispersion of ZCS and better interface connection, thus further boosts the migration of photogenerated charge carriers and protect the photocorrosion of ZCS, ultimately improves the photocatalytic hydrogen production. Optimal ZCS content of 10 wt% exhibited a significantly enhanced visible light photocatalytic hydrogen production efficiency of 15.08 mmol h−1 g−1, which far surpassed bare ZCS at 7.62 times. Furthermore, the ZCS@h-M showed outstanding stability during photocatalytic hydrogen production over a number of cycles. [ABSTRACT FROM AUTHOR]

This work provides a hydrothermal method to synthesize noble-metal-free materials core-shell CdS@MnS nanorods as catalysts for photocatalytic hydrogen evolution. To characterize the hydrothermally synthesized products, XRD, UV–vis DRS, TEM, HRTEM and XPS were carried out. Extraordinarily high hydrogen evolution rate under visible light irradiation (λ ≥ 400 nm) can be achieved. TEM images show that MnS is uniformly coated on the surface of CdS nanorods. The hydrogen evolution results show that coated MnS can significantly improve the photocatalytic efficiency of CdS nanorods. The hydrogen evolution rate reaches an optimal value up to 15.55 mmol g −1 h −1 with MnS content of 5 wt% and is about 3.44 times higher than that of bare CdS nanorods. The large and intimate coaxial heterojunction between CdS nanorod core and MnS thin shell benefits the separation and transportation of photo-induced charge carriers. [ABSTRACT FROM AUTHOR]

CdS@BN NRs core-shell photocatalysts for hydrogen evolution were synthesized by a solvothermal and chemical adsorption method. CdS NRs coated by 5 wt% boron nitride (BN) shell exhibited remarkably visible-light photocatalytic hydrogen evolution activity of up to 30.68 mmol g−1 h−1, nearly 6.79 times higher than that of pure CdS NRs, and the apparent quantum efficiency at 420 nm was 7.5%. Transmission electron microscopy showed the CdS NRs were coated with a thin (~5 nm) BN layer, which together with the hydrogen evolution results proved the photocatalytic ability of CdS NRs was significantly improved. The hydrogen evolution rate of CdS NRs coated by 5 wt% BN remained at 91.4% after four cycles, indicating the photocorrosion of CdS NRs was effectively alleviated. Moreover, the large and close coaxial interfacial contact between the CdS core and the BN shell was beneficial to the separation and transfer of photogenerated electron-hole pairs. Proposed mechanism of photocatalytic H 2 evolution over CdS@BN NRs. Image 1 • Core-shell CdS@BN NR photocatalysts were prepared by a solvothermal and chemical adsorption self-assembly method. • The photocatalytic H 2 -evolution activity and stability were greatly enhanced by coating boron nitride shells. • CdS NRs added with 5 wt% boron nitride showed an excellent H 2 -evolution rate of 30.68 mmol g−1 h−1. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Porous g-C 3 N 4 was prepared by a facile bacteria-motivated liquid etching method. • The pore structure of g-C 3 N 4 was significantly optimized by bacterial etching. • The porous structure may facilitate the transfer of carriers. • The porous g-C 3 N 4 performs well in photocatalytic H 2 evolution. Abstract Porous graphitic carbon nitride (g-C 3 N 4) was successfully synthesized by a simple bacterial etching method. Compared with bulk g-C 3 N 4 , the specific surface area of the porous g-C 3 N 4 increased from 14.48 to 75.22 m2/g, and its photocatalytic activity was significantly enhanced by a factor of 2.49 for photocatalytic H 2 evolution. The enhancement of photocatalytic activity is attributed to the enlarged specific surface area, remarkably narrowed band gap (2.28 eV) and fast electron transportation benefit from the porous structure. [ABSTRACT FROM AUTHOR]

By surface-decorating Pt TiO 2 hybrid catalyst with MoS 2 nanosheets, we prepared a new MoS 2 /Pt TiO 2 ternary system as high-performance photocatalysts. The ternary MoS 2 /Pt TiO 2 outperforms both the binary MoS 2 TiO 2 and Pt TiO 2 systems in photocatalytic hydrogen evolution with an AQY (apparent quantum yield) value of 12.54% at 420 nm, owing to the unique ternary design that creates more efficient electron transport path and electron-hole separation mechanism. Electrochemical characterization showed that the MoS 2 /Pt TiO 2 ternary electrode afford an efficient pathway of photo-excited electrons from TiO 2 to surface-decorated Pt nanoparticles using MoS 2 and internal Pt nanoparticles as bridges, thus significantly promoting electron transfer, reducing the system overpotential and leading to the activation of more reactive sites. This internal electron transfer pathway (TiO 2 → Pt (internal) → MoS 2 → Pt (surface)) eliminates the need of other metal cocatalysts because the Pt nanoparticles play two roles of storing the conduction band electrons of TiO 2 and acting as co-catalyst for reduction of protons to hydrogen. This unique ternary metal-semiconductor heterojunction for efficient photocatalytic hydrogen evolution provides a meaningful reference for reasonable design of other hybrid photocatalysts. [ABSTRACT FROM AUTHOR]

The defect engineering is of vital importance for electrocatalysts because it can provide an additional yet advanced tier to further boost catalysis, especially for ultrathin nanosheets of transitional metal compounds with a high surface to bulk ratio and more importantly the ability to engineer the defect along the longitudinal direction of the grain boundaries. Herein, we developed super-thin and ordered face-centered cubic VN nanosheets with grain boundaries using a new facile and in-situ method. The structural and morphological properties of the prepared samples were investigated, finding that the temperature has significant effects on the distribution of sheets. The thickness of nanosheets is only 1.3 nm the same as that of three cubic VN crystal unit cells, which is pivotal to the electrochemical reaction. The detailed electrocatalysts results show that the VN nanosheets (NSs) exhibit interesting ORR performance with the onset potential of 0.93 V and a half-wave potential of 0.86 V. The evenly distributed VN NSs display the highest durability with only 5% attenuation after 50000s operation for the oxygen reduction reaction. We provide a new strategy to synthesize super-thin nitrides nanosheet structure, highlighting the strong correlation between surface engineering and the performance of electrocatalysts for potential practical oxygen reactions. • Highly active atomic-thin VN nanosheets anchored on layers of N-doped carbon are prepared by an in-situ and facile method. • The thickness of the atomic-thin VN nanosheets is only 1.3 nm the same as that of three VN unit cells. • The VN nanosheet is approximately tens of nanometers in size. • Our results give strong evidence to prove the correlation between the crystal plane of nanosheet and ORR performance. [ABSTRACT FROM AUTHOR]

In this work, a series of highly efficient and noble metal-free Co 0.2 Cd 0.8 S/g-C 3 N 4 nanocomposites were synthesized via a facile one-step hydrothermal strategy. The Co 0.2 Cd 0.8 S/g-C 3 N 4 composites modified with 10 wt% g-C 3 N 4 (CCNE10) exhibited the highest photocatalytic hydrogen evolution rate, which was 1.85-times as high as that of pure Co 0.2 Cd 0.8 S and 7.85-times higher than CdS. Furthermore, the CCNE10 catalyst was very stable in cycling hydrogen production, which is ascribed to the unique g C 3 N 4 modified CdS@CoS structure with fast photogenerated electron transport character. [ABSTRACT FROM AUTHOR]

A simple hydrothermal process was developed to synthesize Co 0.5 Cd 0.5 S/g-C 3 N 4 composite photocatalysts. The crystal structure and surface morphology were characterized with XRD and TEM. The chemical state on the material surface, the chemical structure as well as the ultraviolet–visible light response of the photocatalyst were investigated with XPS and UV–vis DRS. The hydrogen production experiments indicated that the Co 0.5 Cd 0.5 S catalyst exhibits enhanced efficiency and stability with the addition of g-C 3 N 4 , which effectively inhibited the occurrence of photo-corrosion and promoted the separation efficiency of the photogenerated electron–hole pairs. The highest rate of H 2 generation from the composite catalyst is up to 6.31 mmol g −1 h −1 under visible light (λ > 400 nm). [ABSTRACT FROM AUTHOR]

The exploitation of efficient OER electrocatalysts has become the key to realize the commercial-application of H 2 production from electrocatalytic water splitting. In this research, the novel defect-induced N, S co-doped carbon-supported Co 3 C nanoparticles were successfully fabricated as OER electrocatalyst by combination of wet-impregnation treatment of Co/sulfonated polybenzimidazole (sPBI) and subsequent thermal annealing treatment, which was denoted as Co 3 C/CNS-X (X=700, 800, 900) electrocatalyst. Among them, Co 3 C/CNS-800 delivered the more favorable architecture due to its large specific surface area, high dispersion of Co 3 C nanoparticles and especially the generation of abundant defects sites, which not only improved its conductivity and the amounts of electrocatalytically active sites but also imparted the extremely important functionality in accelerating the interfacial electron-transfer and facilitated the adsorption ability of intermediates, thus exerting the extraordinary activities for catalyzing OER. What's more, there were some evidences demonstrating the generation of the strong interfacial interactions through the Co-N coordination bonds and the formation of more pyridinic-N species though annealing treatment, which allowed the structural stability to be further strengthened and simultaneously gave impetus to the O 2 release for the reduction of OER overpotential. In recognition of these approvable structural characteristics, the Co 3 C/CNS-800 exhibited the lowest overpotential of 300 mV at an anodic current density of 10 mA cm−2, and a small Tafel slope of 70 mV dec−1 in 1 M KOH electrolyte as well as a long durability. [Display omitted] [ABSTRACT FROM AUTHOR]

The photocatalytic H 2 evolution rate of Pt and NVC co-loaded g-C 3 N 4 is much higher than that of only Pt or NVC loaded g-C 3 N 4 , which is attributed to the strong synergy between Pt and NVC, where NVC promotes H 2 O activation, and Pt boosts proton reduction. [Display omitted] • N-doped VC (NVC) and Pt were combined as a multifunctional cocatalyst to boost photocatalytic H 2 evolution. • An excellent photocatalytic H 2 evolution rate about 40 μmol/h was achieved over NVC and Pt co-loaded g-C 3 N 4. • High activity is attributed to the enhanced surface catalytic reaction where NVC activates H 2 O and Pt accelerates proton reduction. • The introduction of NVC also greatly promotes carrier separation then facilitates activity. Cocatalyst loading is an efficient strategy to accelerate the hydrogen evolution reaction, which is the final crucial process to complete photocatalytic hydrogen production and realize solar-to-hydrogen conversion. Herein, we report that N-doped vanadium carbide (NVC) is combined with Pt to form a multifunctional cocatalyst capable of enhancing carrier separation, activating H 2 O, and accelerating H 2 evolution. Our designed Pt/NVC/C 3 N 4 displays much higher photocatalytic activity than g-C 3 N 4 loaded with Pt or NVC. The photocatalytic H 2 evolution rate of Pt/NVC/C 3 N 4 reaches 40 μmol/h, which is three times and one hundred times higher than that of Pt/C 3 N 4 and NVC/C 3 N 4 , respectively. The significantly enhanced photocatalytic activity of Pt/NVC/C 3 N 4 is attributed to the partial synergy between Pt and NVC, where NVC promotes carrier separation and activates H 2 O, and Pt is responsible for boosting proton reduction. Our work demonstrates that hybrid cocatalysts exhibit superior performance compared to traditional single-component cocatalysts, providing guidance for exploring highly active cocatalysts for photocatalysis. [ABSTRACT FROM AUTHOR]

The exploration of cost-effective and efficient bifunctional catalysts for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is currently a critical obstacle in the development of regenerative fuel cells and rechargeable metal-air batteries. In this reported study, we detail the synthesis of an N-doped hollow graphene nanospheres/CNTs architecture with encapsulated Fe 3 C@C nanoparticles (Fe 3 C@C-NGns-NCNTs) via a facile, in situ fabrication method. The resulting catalyst had a high specific surface area (450 m2 g−1) with a hierarchical meso -macroporous structure. In an alkaline electrolyte, the catalyst manifested remarkable bifunctional catalytic activity with a half-wave potential for ORR of ca. 23 mV that was higher than that produced by a commercial Pt/C and the former had a small overpotential of 412 mV at a current density of 10 mA cm−2 for the OER. The ΔE (oxygen electrode activity parameter) value for the Fe 3 C@C-NGns-NCNTs was only 0.787 V. We posit that the high electrocatalytic performance of this catalyst was due to the following factors: (1) a synergistic effect, induced by the presence of multiple types of active sites, including Fe 3 C@C nanoparticle, nitrogen dopant and possible Fe-N x -C sites; (2) the unique hollow graphene nanospheres/CNTs architecture, which facilitated the adsorption/diffusion of reactants/products and rapid electron transfer; and (3) the high degree of graphitization of the catalyst that improved the electrocatalytic stability. • N-doped hollow graphene nanospheres/CNTs architecture with encapsulated Fe 3 C@C nanoparticles was prepared by a facile in situ method. • The catalyst shows a high surface area and hierarchical porous structure. • The catalyst shows a high ORR and OER performance. [ABSTRACT FROM AUTHOR]