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Integrating electrochemical nitrate reduction to ammonia (NRA) and the sulfion oxidation reaction (SOR) to construct a coupled electrolysis system is expected to realize the collective value-added recycling of nitrate and sulfion wastes. In this study, we developed a dimethylamineborane (DMAB)-involved post-modification strategy to convert pre-synthesized Co-MOF/NF into DMAB–Co-MOF/NF, which could serve as a bifunctional precatalyst and in situ reconstructed into heterogeneous CoOOH/Co(OH)2/NF (for NRA) and amorphous B–Co–S/NF (for SOR) as active phases under electrocatalytic conditions, respectively. With demonstrated excellent nitrate-to-ammonia activity over the reconstructed CoOOH/Co(OH)2/NF (NH3 yield rate: 0.238 mmol h−1 cm−2 and NH3 faradaic efficiency: 94.16%) and enhanced sulfion recycling capability over the reconstructed B–Co–S/NF (100 mA cm−2 of the SOR@0.268 V vs. the reversible hydrogen electrode), coupling NRA to the SOR based on these two electrocatalysts could realize energy-efficient collective value-added recycling of nitrate and sulfion into ammonia and sulfur (50 mA cm−2@1.062 V cell voltage). [ABSTRACT FROM AUTHOR]

Rational construction of advanced electrocatalysts that can realize coupling of the hydrogen evolution reaction (HER) with electrooxidation of organic compounds, rather than the sluggish oxygen evolution reaction, will make the catalytic efficiency of electrolytic hydrogen production more efficient. Herein, we report a bifunctional chainmail catalyst composed of NiGd nanoparticles wrapped by N-doped graphene shells (NiGd@N–C) for both the HER and methanol oxidation reaction (MOR). Benefiting from the unique architecture, the NiGd@N–C catalyst exhibits excellent HER activity under alkaline conditions (η10 = 45 mV), and also performed with high activity for selective methanol oxidation to formate. Theoretical analysis verifies that introducing the rare earth Gd element could enhance electron penetration from the NiGd core to the N–C shell, which was responsible for enhanced HER and MOR performance. Impressively, the methanol–water co-electrolysis system based on bifunctional NiGd@N–C catalysts only needs 1.34 V of cell voltage to reach 10 mA cm−2 for co-electrosynthesis of hydrogen and formate. [ABSTRACT FROM AUTHOR]

Rationally designing advanced electrocatalysts and innovative energy-efficient electrolysis systems for converting carbon dioxide (CO2) into value-added chemicals or fuels is of significance yet challenging. As for the electrochemical CO2 reduction reaction (CO2RR), the electrocatalytic efficiency is largely limited by the CO2 adsorption and activation capability of active sites. Herein, B-doped Bi nanosheet arrays grown on Cu foam are synthesized by a galvanic replacement combined with in situ doping strategy. It was demonstrated that the B dopant could serve as Lewis acid sites for promoting the adsorption of CO2, and more importantly, regulate the electronic structure and crystallinity of Bi nanosheet arrays, and create abundant amorphous/crystalline two-phase interfaces, which boost the CO2RR activity. Moreover, coupling the CO2RR with the thermodynamically more favorable methanol oxidation reaction (replacing the kinetically sluggish oxygen evolution reaction) within a pH-asymmetric electrolysis system could realize highly efficient pair-electrosynthesis of formate with a much-reduced energy consumption compared with a conventional electrochemical CO2RR system. [ABSTRACT FROM AUTHOR]

Coupling the hydrogen evolution reaction (HER) with the glycerol oxidation reaction (GOR) can efficiently suppress the sluggish oxygen evolution reaction (OER), boost hydrogen production efficiency and meanwhile obtain glycerol-derived value-added anodic products. Developing active and robust HER-GOR bifunctional electrocatalysts is of vital significance for constructing a water–glycerol co-electrolysis system. Herein, Ru-doped heterostructured nickel phosphide/nitrogen-doped carbon (Ru–NixPy/N–C) hybrid nanosheet arrays were fabricated by controlled phosphorization of NiRu-based metal–organic framework nanosheet array precursors. With the synergism of the hetero-phase Ni2P–Ni12P5 interface effect and Ru-doping induced strain effect, the Ru–NixPy/N–C arrays grown on Ni foam (Ru–NixPy/N–C/NF) could efficiently electrocatalyze both the HER (−10 mA cm−2@ −0.031 V vs. RHE) and GOR (10 mA cm−2 @1.32 V vs. RHE). Remarkably, the Ru–NixPy/N–C/NF‖‖Ru–NixPy/N–C/NF two-electrode system could enable simultaneous efficient H2 generation and formate electrosynthesis from a 1 M KOH solution containing 0.1 M glycerol, deriving a 10 mA cm−2 current density at a low cell voltage of 1.36 V. [ABSTRACT FROM AUTHOR]

Reducing the high energy of water splitting caused by a sluggish oxygen evolution reaction (OER) is essential, but still a challenge. Replacing the anodic OER with a thermodynamically favorable organic upgrading reaction not only reduces the operating voltage, but also produces value-added chemicals, which is regarded as a win–win strategy. In this work, MOF-derived Os-doped NixP/N-doped carbon composite nanosheet arrays on nickel foam (Os–NixP/N–C/NF) are fabricated as a bifunctional catalyst for oxidizing methanol to value-added formate while simultaneously facilitating H2 production. Taking advantage of synergistic structural and compositional properties, the obtained Os–NixP/N–C/NF exhibits high faradaic efficiency for generating anodic formate (92%) and cathodic H2 (100%). Moreover, the two electrode systems only need 1.43 V to achieve an electrolytic current density of 10 mA cm−2 in 1.0 M KOH with 1.0 M methanol. [ABSTRACT FROM AUTHOR]

The design of electrocatalysts with favorable morphologies and surface compositions is an effective strategy to prepare electrocatalysts for the hydrogen evolution reaction (HER). Herein, a polyaniline (PANI) modified mesoporous ruthenium film supported on carbon paper (mRu@PANI/CP) was successfully synthesized by a two-step electrodeposition method at room temperature. With the mesoporous film structure and PANI modification, mRu@PANI/CP displayed superior HER catalytic activity with overpotentials of 30 mV (0.5 M H2SO4), 27 mV (1.0 M KOH), and 24 mV (1.0 M PBS), respectively, at a current density of 10 mA cm−2. This work not only provides a powerful route to prepare a mesoporous Ru film, but also offers a useful interface functionalization strategy to further enhance its electrocatalytic performance, beyond the HER. [ABSTRACT FROM AUTHOR]

The electrochemical nitrogen reduction reaction (NRR) is considered as a facile and sustainable strategy for ammonia production. Design of high-performance electrocatalysts is the crucial issue for the NRR. Herein, we present a one-pot reduction method to directly synthesize bimetallic Ag3Cu porous networks (Ag3Cu BPNs). Owing to their porous networks and bimetallic composition, the Ag3Cu BPNs exhibit outstanding NRR performance with a high NH3 yield of 24.59 μg h−1 mgcat.−1 and faradaic efficiency of 13.28% at −0.5 V vs. the reversible hydrogen electrode. This study proposes a facile and scalable route for the development of metallic porous networks with an interconnected structure and desired components for electrochemical ammonia production. [ABSTRACT FROM AUTHOR]