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As a high calorific and zero carbon energy source, hydrogen has received a significant amount of attention in recent years. In this work, the amorphous molybdenum sulfide was uniformly and orderly wrapped around the surface of Ni9S8/NF nanowires by electrodeposition to obtain a-MoSX@Ni9S8/NF nanoflower rods. A low overpotential of 138 mV (@10 mV cm−2) at room temperature was achieved for a-MoSX@Ni9S8/NF with a high electrochemically active surface area. An external thermal field could reduce the interfacial charge transfer resistance between the electrode and the electrolyte and promote the electrochemical hydrogen evolution reaction (HER). The a-MoSX@Ni9S8/NF showed excellent hydrogen precipitation performance of 72 mV (@10 mV cm−2) under 80 °C. The a-MoSX@Ni9S8/NF owned good reproducibility and durability after 5000 cycles in acidic media. The Faraday efficiency of the composite can reach 92.6%. This work provided a meaningful perspective on the design of electrochemical HER catalysts and external field assisted HER. [ABSTRACT FROM AUTHOR]

Various reduced graphene oxide supported CuS (RGO-CuS) composites were obtained via a hydrothermal way in this work. The as-obtained RGO-CuS with a low bandgap of ~1.24 eV showed significant light absorption in near-infrared (NIR) region. In acidic media, the optimized 0.1RGO-CuS needed an overpotential of 179 mV (at 10 mA cm−2) to trigger the hydrogen evolution reaction under NIR light. And the lowest Tafel slope of 0.1RGO-CuS (61 mV dec−1), suggesting that the photoelectrocatalytic hydrogen evolution was performed under the Volmer-Heyrovsky mechanism. The 0.1RGO-CuS displayed a good durability after 5000 cycles in acid. According to the results of EIS measurement, both NIR irradiation and RGO modification could effectively lower charge transfer resistance and improve charge transport rate of the photoelectrochemical process. The introduction of RGO could improve the electron and hole separation ability of the photoelectrochemical process, which resulted in an enhanced photoelectrocatalytic HER performance. [Display omitted] • A p-type RGO-CuS composite with bandgap of ~1.24 eV was synthesized in this work. • The RGO-CuS showed remarkable NIR light response. • The noble metal free RGO-CuS composite exhibited good and stable HER performance. [ABSTRACT FROM AUTHOR]

• A MWCNTs-MoS 2 -MoO 3 HER photoelectrocatalyst with low band gap was obtained. • The MWCNTs-MoS 2 -MoO 3 exhibited NIR enhanced electrocatalytic HER performance. • NIR irradiation and MWCNTs could improve charge separation efficiency. • MoS 2 -MoO 3 heterostructure and bridging S 2 2− would improve the HER performance. [Display omitted] As a new zero-carbon energy with high calorific value, hydrogen has attracted extensive attention in recent years. In this work, multiwalled carbon nanotubes modified molybdenum sulfide and molybdenum oxide heterostructure (MWCNTs-MoS 2 -MoO 3) was obtained via a simple hydrothermal method. The low band gap of 0.02MWCNTs-MoS 2 -MoO 3 (1.15 eV) endowed a good near-infrared (NIR) light response. The conduction band position of 0.02MWCNTs-MoS 2 -MoO 3 (−0.63 V vs. reversible hydrogen electrode (RHE)) was negative enough to produce hydrogen. Compared with pure MoS 2 , the formation of MoS 2 -MoO 3 heterostructure and introduction of MWCNTs generated better photoelectrochemical activity and NIR irradiation improved photoelectrocatalytic (PEC) hydrogen evolution performance in wide pH range. The 0.02MWCNTs-MoS 2 -MoO 3 had superior overpotential (68 mV @ 10 mA cm−2) and Tafel slope (56 mV dec−1) in acidic media. The NIR improved PEC hydrogen evolution activity of 0.02MWCNTs-MoS 2 -MoO 3 in acidic media could be explained by Volmer-Heyrovsky mechanism. The presence of large amount of bridging S 2 2− in 1 T/2 H phase MoS 2 and the synergistic effect between MWCNTs and MoS 2 -MoO 3 heterostructure made a joint effect on the photoelectrocatalytic hydrogen evolution reaction (HER). NIR irradiation could increase the charge transport rate. The introduction of MWCNTs and heterostructure formation could increase the charge transport rate and improve the electron and hole separation ability of 0.02MWCNTs-MoS 2 -MoO 3 as well. [ABSTRACT FROM AUTHOR]

[Display omitted] • rGO-MoS 2 composite with remarkable NIR light response was obtained. • rGO-MoS 2 exhibited good and stable HER performance in a wide pH range. • rGO and NIR light have synergistic effect on the photoelectrocatalysis of MoS 2. • The photoelectrocatalytic HER mechanism by rGO-MoS 2 under NIR light is proposed. This work presents an effective way of enhancing MoS 2 -mediated electrocatalytic hydrogen evolution, by exploiting the synergistic effect of reduced graphene oxide (rGO) and near-infrared (NIR) light. Various rGO-MoS 2 composites were obtained via hydrothermal method. The optimized composite, 0.2rGO-MoS 2 exhibited enhanced electrocatalytic hydrogen evolution activity in a wide pH range under NIR irradiation, without adding noble metal. The overpotentials of 0.2rGO-MoS 2 at 10 mA cm−2 in acidic and alkaline media were 146 and 314 mV, respectively. The corresponding Tafel slopes in acidic and alkaline media were 51 and 80 mV dec−1, respectively. In both media, the electrocatalytic hydrogen evolution by 0.2rGO-MoS 2 under NIR irradiation was attributed to the Volmer-Heyrovsky mechanism. 0.2rGO-MoS 2 also had a good reproducibility and durability under NIR light irradiation after 5000 cycles and 24 h of continuous electrolysis in both media. Furthermore, the roles of rGO and NIR irradiation in the electrocatalytic hydrogen evolution by MoS 2 were investigated. [ABSTRACT FROM AUTHOR]

The nitrogen-doped carbon nanofiber derived from low and high proportion polyaniline doped bacterial cellulose (BC) was obtained via polymerization followed by pyrolysis. The resulting products were named LN-BC and HN-BC accordingly. Platinum nanoparticles modified LN-BC and HN-BC was then prepared (Pt@LN-BC and Pt@HN-BC) via electrochemical deposition. The morphologies of LN-BC and HN-BC indicated that the BC lost its nanowire structure after polyaniline modification and pyrolysis under nitrogen atmosphere. Platinum nanoparticles with diameters ranging from 3 to 5 nm can be well dispersed in the HN-BC support. The HER performance of Pt@LN-BC and Pt@HN-BC was fully investigated. Electrochemical results showed that the Pt-based catalysts had better HER activity than the Pt free catalysts in acid, indicating the HER activity was mainly from Pt. Besides, Pt@HN-BC had better HER activity than Pt@LN-BC in acid, suggesting N-doping rate was an important factor in enhancing HER activity. And the 10Pt@HN-BC (deposition for 10 s) with 4.38 wt% Pt loading was the best HER catalyst among the Pt@HN-BC. The onset potential (@ −1 mA cm −2 ) and overpotential (@ −10 mA cm −2 ) of the 10Pt@HN-BC in 0.5 M H 2 SO 4 is −18 and −47 mV, respectively. The corresponding Tafel slope was −35 mV dec −1 , which is quite comparable to that of Pt/C (10 wt%). The electrochemical double layer capacitance (C dl ) and turnover frequency (TOF) were estimated and presented in the work. Long-term stability test confirmed that the 10Pt@HN-BC had excellent stability, which was important for practical application. [ABSTRACT FROM AUTHOR]

Snowflake-like Cu 2 S/MoS 2 heterostructures with varied compositions were constructed via a two-step hydrothermal method. The 45-Cu 2 S/MoS 2 with 45 wt% Cu 2 S was found as the optimum catalyst, which displayed photothermal enhanced hydrogen evolution reaction (HER) performance under near infrared (NIR) irradiation. After electrochemical deposition of a tiny amount of Pt (45-Cu 2 S/MoS 2 /Pt-100s), Schottky barrier was formed between Pt nanoparticles and MoS 2 nanosheets. Using 45-Cu 2 S/MoS 2 /Pt-100s as an electrocatalyst, low overpotential of 78 mV (@10 mV cm−2) and Tafel slope of 48 mV dec−1 were achieved with the assistance of NIR irradiation. The photoelectrochemical (PEC) hydrogen production performance of 45-Cu 2 S/MoS 2 /Pt-100s was also investigated. The optimal conversion efficiency of 45-Cu 2 S/MoS 2 /Pt-100s could reach 0.78% at 0.57 V (vs. reversible hydrogen electrode (RHE)). The control of the internal geometric and electronic structure of the catalysts and the aid of photothermal effect in this work provide new ideas for designing high-efficiency hydrogen evolution catalysts. [Display omitted] • Snowflake-Like Cu 2 S/MoS 2 /Pt composite was prepared for (photo)electrocatalysis. • The Cu 2 S/MoS 2 /Pt composite showed NIR enhanced catalytic hydrogen evolution activity. • NIR induced photothermal effect could improve the interfacial charge transport rate. • Its p–n heterojunction and Schottky barrier boost the e–-h+ transfer and separation. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting has been confirmed as one of the effective methods to produce hydrogen. Effective electrocatalyst with low dynamic overpotential and long durability is an important factor in hydrogen evolution reaction (HER). In present work, a cobalt oxide derived from zeolitic imidazolate framework (ZIF-67) was anchored on bacterial cellulose (BC) to construct a ZIF-67/BC nanostructure firstly. Then, trace amount of palladium and platinum bimetal were deposited on the surface of ZIF-67/BC for various times via electrodeposition to form xPtPd@ZIF-67/BC (x was the electrodeposition time). The optimized electrocatalyst, 10PtPd@ZIF-67/BC with 0.07 wt% Pt and 0.23 wt% Pd loading showed superior electrochemical activity and HER performance in both acidic and alkaline media. The overpotential (@ 10 mA cm−2) was 59 and 33 mV in 0.5 M H 2 SO 4 and 1.0 M KOH, respectively. The corresponding Tafel slope was 17 and 87 mV dec−1, respectively. The 10PtPd@ZIF-67/BC also displayed a good durability after 5000 cycles and 24 h of continuous electrolysis in 0.5 M H 2 SO 4 and 1.0 M KOH. The ZIF-67/BC template could effectively enhance the H 2 O adsorption and improve dispersion of noble metalic nanoparticles. The presence of Pd enhanced hydrogen adsorption and further increased the electrocatalytic performance of 10PtPd@ZIF-67/BC. Image 1 • A ZIF-67 derived CoO anchored bacterial cellulose template (ZIF-67/BC) was obtained. • Pt and Pd nanoparticles were electrodeposited on the ZIF-67/BC to construct a HER electrocatalyst. • The optimized electrocatalyst showed superior HER performance in wide pH ranges. [ABSTRACT FROM AUTHOR]