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• Co doped MoS 2 was decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) by a solvothermal process. • The lattice spacing of (1 0 0) plane of Co-MoS 2 was slightly narrow than that of MoS 2. • The as-prepared Co-MoS 2 /NCFCP hybrids showed enhanced electrochemical activity for HER. In this paper, Co-doped MoS 2 (Co-MoS 2) with various Co/Mo mole ratio (6%–12%) decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) (Co-MoS 2 /NCFCP) is fabricated by a solvothermal method as an efficient electrocatalyst for hydrogen evolution reaction (HER). The NCFCP substrate is prepared by electrochemical deposition of polypyrrole on carbon paper followed by heat treatment. The obtained 9% Co-MoS 2 /NCFCP hybrid catalyst exhibits an excellent electrocatalytic HER activity with a low overpotential of 174 mV at 10 mA cm−2, a small Tafel slope of 52 mV dec−1 and long-term stability. Thus, Co-MoS 2 /NCFCP hybrid holds high potential as an efficient earth-abundant electrocatalyst material for HER. [ABSTRACT FROM AUTHOR]

[Display omitted] As a promising dopant, electron deficient B atom not only tunes the electronic structure of electrocatalysts for improving their intrinsic catalytic activities, but also combines with hydroxy radical as strong adsorption sites for accelerating the water dissociation during the hydrogen evolution reaction (HER). In this paper, we report an electrocatalyst based on boron-modified Ru anchored on carbon nanotubes (B-Ru@CNT) that shows impressive HER activity in acidic and alkaline media. The boron-rich closo -[B 12 H 12 ]2- borane was selected as a moderately strong reductant for the in situ reduction of a Ru salt, which yielded B-doped Ru nanoparticles. The experimental and theoretical results indicate that the incorporation of B not only weakens the Ru-H bond and downshifts the d-bond centre of Ru from the Fermi level by reducing the electron density at Ru but also accelerates the water dissociation reaction by providing B sites, which strongly adsorb OH* intermediates, and nearby Ru sites, which act as sites for the adsorption of the H* intermediate, thus boosting the HER performance and enhancing the HER kinetics. As a result of the tuning of the electronic structure via B doping, B-Ru@CNT showed excellent HER performance, yielding overpotentials of 17 and 62 mV at a current density of 10 mA cm−2 in alkaline and acidic solutions, respectively. These results indicate that our synthetic method is a promising route to B-doped metallic Ru with enhanced pH-independent HER performance. [ABSTRACT FROM AUTHOR]

Synthesis of catalysts with high activity for hydrogen evolution reaction (HER) has been a hot topic in electrocatalysis. In this paper, using MIL-88A(Fe) metal-organic complex, polyoxometalate (POM) and H2PtCl6 as starting materials, hierarchic and low Pt0-loading micro-rods (denoted as Pt-POMFe, i.e. Pt-PW12Fe or Pt-PMo12Fe) have been synthesized, in which the Pt0 nanoparticles can be stabilized by POM. The Pt-PW12Fe micro-rod containing [PW12O40]3- polyoxoanion component (0.30% Pt0-loading) which retains the spindle structure of its parent MIL-88A(Fe) exhibits a low overpotential of 28 mV at current density of 10 mA·cm−2 for HER that is close to the electrocatalytic effect of commercial Pt/C (ca. 20% Pt0-loading). Such high electrocatalytic reactivity is mainly caused by the synergistic effect of the three components of POM, Pt0, and Fe3O4@C. The structure effectively increases the active sites of the catalyst and improves its conductivity and stability. The Pt-POMFe catalyst extends a new family of MOF-POM functional materials and provides a new concept to the design and synthesis of highly-efficient and low-cost electrocatalyst for hydrogen production. [ABSTRACT FROM AUTHOR]

Developing cost‐effective and highly active hydrogen evolution reaction (HER) electrocatalysts is of pivotal importance in the roadmap of hydrogen economy. Increasing active sites and improving conductivity are two effective strategies to optimize the performance of electrocatalyst. In this paper, we report a highly active HER catalyst consisting of ultra‐small molybdenum carbide nanoparticles uniformly entrapped in mesoporous carbon microspheres (Mo2C@MCS) fabricated by in situ synthesis. In 1 M KOH, the catalyst exhibits an excellent HER performance with a pretty low overpotential (134 mV at current density of 10 mA cm−2) and a small Tafel slope (51 mV dec−1), which exceeded the currently reported un‐doped Mo2C catalyst. The excellent HER performance is attributed to the abundant active sites provided by the ultra‐small Mo2C nanoparticles as well as the superior conductivity originated from carbon matrix and the intimate contact between Mo2C nanoparticles and mesoporous carbon wall. [ABSTRACT FROM AUTHOR]

• Strong oxidation treatment improved the surface area and active sites of CNT. • Platinum particles exhibit a high dispersion on Carbon nanotubes (CNT). • Pt/CNT and Pt/CNT-H nanohybrids present a low overpotential of 28 and 19 mV. • Pt/CNT and Pt/CNT-H nanohybrids show a low Tafel slopes. • The long-time test indicated Pt/CNT-H catalyst had a good stability. A kind of electro-catalyst with high efficiency is proposed for hydrogen evolution reaction in this paper and such an electro-catalyst exposes its outstanding electro-catalytic performance and high stability in the hydrogen evolution reaction in 0.5 M H 2 SO 4 electrolyte. In detail, at the current density of 10 mA cm−2, the overpotential of Pt/CNT-H (19 mV) was significantly lower than that of commercial Pt/C catalyst (38 mV). The excellent catalytic performance of such kind of electro-catalyst shall be contributed to synergistic effect caused by Platinum nano-particles and carbon nanotubes and the cross-linked three-dimensional structures. [ABSTRACT FROM AUTHOR]

Oxygen evolution is kinetically the key step in the photocatalytic water splitting, but it is negatively affected by the poor charge transport properties. However, this can be modified by the loading of cocatalysts on the surface of a semiconductor which could form heterojunctions to boost the charge separation and lower the activation potential for O 2 evolution. In this paper we demonstrate that the poor O 2 evolution activity of photocatalytic water splitting of the multiferroics BiFeO 3 can be enhanced when a proper cocatalyst like IrO 2 nanoparticles are deposited on the surface and proper electron scavenger is used. The choice of the persulfate, S 2 O 8 as electron scavenger is influenced by its high redox potential and its close position to the valence band of BiFeO 3 compared to other commonly used scavengers. Another interesting information was revealed by using transient absorption spectroscopy under different environment namely, inert, oxidizing and reducing. The absorption peak of holes was identified and correlated to the strong absorption around 560 nm The hole absorption peak showed a 50% decrease in the absorption intensity after 2.5 μsec indicating that holes are captured by IrO 2 nanoparticles on the surface. O 2 evolution of multiferroics, especially BiFeO 3 has been less investigated. Therefore, the development of efficient photocatalytic materials has relied on both photocatalysts and cocatalysts. Identification of the photogenerated charge absorption peak from transient absorption spectra facilitate the evaluation of the IrO 2 loading effect on the charge separation and the overall O 2 evolution process. • Visible light photocatalytic OER of BiFeO 3 nanoparticles. • Enhancement of OER by loading IrO 2 nanoparticles as cocatalyst on the surface of BiFeO 3. • Volcanic type dependance of oxygen evolution and IrO2 loading content. • Identification of the absorption signal of the photogenerated charges by TAS, measured in N 2 , MeOH and O 2 atmosphere. • A signal at 560 nm was assigned to holes as indicated from TAS measurements. [ABSTRACT FROM AUTHOR]

A high active and stable bifunctional oxygen electrocatalyst of Co–CoO multiphase nanoparticles (NPs) encapsulated in N,S co-doped carbon shells (Co–CoO@NSC) is designed and constructed by in-situ S doping of ZIF-67 with thiourea and subsequent pyrolysis, which not only generates small Co–CoO NPs due to the steric effect, but also creates more active sites and defects. First-principles simulations reveal that in-situ S-doping optimizes the charge distribution of Co–N 4 sites and Co–O–C bonds, which reduces the formation energy of *OOH and then improves the ability of oxygen adsorption and hydrogen peroxide desorption. The optimized Co–CoO@NSC exhibits excellent catalytic activity with the overpotential of only 279 mV at 10 mA cm−2 for OER and the half-wave potential of 0.89 V for ORR, outperforming that of most recent reported bifunctional electrocatalysts. Our Co–CoO@NSC catalyst indicates the Δ E (Δ E = E j=10 (OER) − E 1/2 (ORR)) of 0.68 V, which is smaller than the Pt/C + RuO 2 system. Flexible solid-state Zn-air battery with Co–CoO@NSC-5 as air-electrode possesses a high power density (87.7 mW cm−2) as well as good bending flexibility. The simple synthesis method proposed in our paper is beneficial for inspiring the development for high active and stable bifunctional non-noble metal electrocatalysts in next-generation flexible electronic devices. Image 1 • Thiourea-ZIF-67 assembly generates small Co–CoO nanoparticles and more active sites. • In-situ S-doping optimizes the charge distribution of Co–N 4 sites and Co–O–C bonds. • The Δ E of Co–CoO@NSC-5 is ~0.68 V, smaller than the Pt/C + RuO 2 system. • Improved performance toward rechargeable flexible solid-state Zn-air battery. [ABSTRACT FROM AUTHOR]

Hydrogen has been considered one of the best energy carriers to satisfy the increasing demand for clean and renewable energy supply. In this paper, a series of copper-based (CuCo, CuNi, and CuFe) nanoparticles supported on reduced graphene oxide (rGO) were synthesized via a facile one-pot chemical reduction route, and their catalytic performance on hydrogen evolution from ammonia borane (NH3BH3, AB) hydrolysis at room temperature was studied. The results revealed that the Cu0.2Co0.8 nanoparticles (~ 2.1 nm) on rGO exhibited the highest activity, and Co nanoparticles (~ 3.9 nm) on rGO also displayed the excellent performance. Among all the as-prepared Cu0.2Co0.8/rGO catalysts, Cu0.2Co0.8/rGO with 48 wt% nanoparticles exhibits the highest activity with the initial hydrogen production rate values as high as 50.6 mol H2 molmetal−1 min−1, superior to the majority of Cu-based non-noble metal catalysts. The excellent performance could be attributed to the well dispersion of CuCo nanoparticles on reduced graphene oxide. [ABSTRACT FROM AUTHOR]