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Electrochemically reducing CO2 to valuable fuels or feedstocks is recognized as a promising strategy to simultaneously tackle the crises of fossil fuel shortage and carbon emission. Sn‐based catalysts have been widely studied for electrochemical CO2 reduction reaction (CO2RR) to make formic acid/formate, which unfortunately still suffer from low activity, selectivity and stability. In this work, halogen (F, Cl, Br or I) was introduced into the Sn catalyst by a facile hydrolysis method. The presence of halogen was confirmed by a collection of ex situ and in situ characterizations, which rendered a more positive valence state of Sn in halogen‐incorporated Sn catalyst as compared to unmodified Sn under cathodic potentials in CO2RR and therefore tuned the adsorption strength of the key intermediate (*OCHO) toward formate formation. As a result, the halogen‐incorporated Sn catalyst exhibited greatly enhanced catalytic performance in electrochemical CO2RR to produce formate. [ABSTRACT FROM AUTHOR]

Electrochemically reducing CO2 to valuable fuels or feedstocks is recognized as a promising strategy to simultaneously tackle the crises of fossil fuel shortage and carbon emission. Sn‐based catalysts have been widely studied for electrochemical CO2 reduction reaction (CO2RR) to make formic acid/formate, which unfortunately still suffer from low activity, selectivity and stability. In this work, halogen (F, Cl, Br or I) was introduced into the Sn catalyst by a facile hydrolysis method. The presence of halogen was confirmed by a collection of ex situ and in situ characterizations, which rendered a more positive valence state of Sn in halogen‐incorporated Sn catalyst as compared to unmodified Sn under cathodic potentials in CO2RR and therefore tuned the adsorption strength of the key intermediate (*OCHO) toward formate formation. As a result, the halogen‐incorporated Sn catalyst exhibited greatly enhanced catalytic performance in electrochemical CO2RR to produce formate. [ABSTRACT FROM AUTHOR]

Efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) must be developed to realize an inexpensive water-splitting system for large-scale applications. Herein, a novel PdNi carbon nanofiber (PdNi/CNF) catalyst was synthesized by facile electrospinning and carbonization processes. The size and homogeneity of the Pd−Ni alloy nanoparticles (NPs) could be effectively tuned by controlling the molar feed ratio of metal precursors .The morphology and structure of the PdNi/CNFs were characterized, and the working electrodes fabricated from the prepared catalyst mats were directly employed in the HER and OER. The PdNi/CNFs-1:2 catalyst exhibits high catalytic activity in the HER with a low overpotential of 55 mV at a current density of 10 mA cm −2 in an acidic solution. Moreover, under 1 M KOH electrolyte, an overpotential of 187 mV is required in the HER over the catalyst to arrive 10 mA cm −2 and an overpotential of 289 mV is achieved in the OER at the same current density. The superior HER and OER activities of the PdNi/CNFs are attributed to the synergistic effects of the PdNi alloy nanoparticles (NPs) assembled on the CNFs. This work provides a simple route for synthesizing highly efficient bifunctional electrocatalysts from 3d transition metals and a small amount of noble metals for hydrogen and oxygen evolution reactions. [ABSTRACT FROM AUTHOR]

Fe incorporated Ni-based electrocatalysts have emerged as one of the most active oxygen-evolving catalysts under alkaline conditions and deciphering the effect of iron incorporation in enhancing the activity is challenging but critical for the catalyst design. Herein, the as-prepared nanocube Ni-based catalysts underwent a reconstruction process and transformed from γ-NiOOH to β-NiOOH structure by iron incorporation under the applied bias, which was confirmed by in-situ Raman measurement. According to the methanol oxidation current response difference, the hydroxyl adsorption intensity was proposed to be regulated by iron incorporation and the rate-determining step would be the formation of *OOH for Fe-doped β-NiOOH, which was further supported by DFT calculation. This work reveals the effect of iron-doped on the phase structure transform and the regulation of intermediate species elaborately and offers new insight on the understanding of the activity origins for NiFe-based catalysts. [Display omitted] • Potential-induced reconstruction process from γ-NiOOH to β-NiOOH structure by iron incorporation under applied bias. • The Fe-doped β-NiOOH exhibited an overpotential of 247 mV at 10 mA·cm−2 and a Tafel slope of 40.15 mV·dec−1. • The surface coverage of *OH varies in the trend: NiOOH > Fe-doped β-NiOOH > FeOOH. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrochemical activation was employed to prepare Pt/PtTe x heterojunctions. • CV method and DFT calculation both reveal the change of intermediates adsorption. • Pt/PtTe x interface structure reduces H* adsorption and enhances OH* adsorption. • Pt/PtTe x NRs show significantly improved acidic and alkaline HER activity. Increasing OH* adsorption to promote water dissociation while reducing H* adsorption to accelerate hydrogen generation kinetics is an effective solution to further improve the HER activity of Pt-based catalysts. Herein, we have successfully constructed a Pt/PtTe x heterogeneous catalysis interface by electrochemical activation of PtTe 2 nanorods (NRs). The reduction of H* adsorption and significant increase of OH* adsorption was observed on Pt/PtTe x heterojunction via cyclic voltammetry method. Theoretical calculations indicate that Gibbs free energy change (ΔG) of H* is closer to 0.00 eV and ΔG of OH* decreased from 1.36 eV of Pt (111) to −0.40 eV of Pt/PtTe x , which reinforces the experimental results. The rational modulation of adsorbed intermediates endows Pt/PtTe x NRs with exceptionally lower Tafel slopes of 16 and 23 mV dec−1 in 0.5 M H 2 SO 4 and 1.0 M KOH electrolytes, which is among the best reported HER electrocatalysts. [ABSTRACT FROM AUTHOR]

The electron-rich interface of Cu-Co heterostructure nanoparticle an realize the effective separation of photogenerated charge and hole, accelerate the transfer of photogenerated charges, which is a stable and efficient cocatalyst for photocatalytic hydrogen evolution reaction. [Display omitted] • Carbon-coated Cu-Co alloy nanoparticles (CuCo@C) nanoparticles are fabricated. • The bimetallic CuCo has a heterogeneous structure with abundant Cu-Co interfaces. • A large number of photogenerated electrons can be collected at the Cu-Co interface. • The CuCo@C is a high-performance cocatalyst for photocatalytic H 2 evolution. Heterogeneous nano-metal structures are widely used in the field of photocatalysis as an efficient cocatalyst, but the structure–activity relationship has not been elucidated clearly. In this work, a classical CuCo@C nanoparticle with a core of bimetallic CuCo and a carbon shell was used as a cocatalyst to explore and reveal the mechanism of interfacial effect for enhanced photocatalytic hydrogen evolution. It was found that the bimetallic CuCo had a heterogeneous structure with abundant Cu-Co interfaces. The desirable visible-light-driven photocatalytic hydrogen evolution rate of CuCo@C/g-C 3 N 4 was much higher than that of Cu@C/g-C 3 N 4 , Co@C/g-C 3 N 4 , and superior to that of the control group loaded with 1 wt% Pt (Pt/g-C 3 N 4). According to the experimental characterizations and density functional theory calculations, electrons were enriched at the Cu-Co interface, which can promote the electron-hole pairs separation and accelerate charge transfer of the g-C 3 N 4 host photocatalysts. On the other hand, the surface carbon layer and Cu-Co interface modulated the H adsorption free energy on the CuCo@C, which was favorable for hydrogen evolution. It is conceivable that further investigating and tuning different metal interfaces will facilitate the large-scale application of bimetallic cocatalysts. [ABSTRACT FROM AUTHOR]