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Main observation and conclusion: The efficient production and utilization of hydrogen play an important role in the closed loop of energy conversion. It is an urgent need to find low‐cost and high‐performance replacements for platinum‐based catalysts towards hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER). Herein, bifunctional RuNi alloy nanoparticles embedded in oxygen‐doped carbon were prepared via simple annealing of Ru‐doped Ni‐BTC, the limiting current density of which could reach 2.46 mA/cm2 (close to Pt) in 0.1 mol/L KOH for HOR. And the low overpotentials of only 29 mV in 1 mol/L KOH and 62 mV in 0.5 mol/L H2SO4 were needed to reach the current density of 10 mA/cm2 for HER. The effect of alloying and oxygen‐doped graphene contributed to the excellent activity and stability during hydrogen electrocatalysis. This work provides new ideas for the development of novel types of hydrogen electrocatalysts and enriches the application of MOFs in HOR. [ABSTRACT FROM AUTHOR]

The most active catalysts so far successful in hydrogenation reduction of CO2 are mainly heterogeneous Cu‐based catalysts. The complex coordination environments and multiple active sites in heterogeneous catalysts result in low selectivity of target product, while molecular catalysts with well‐defined active sites and tailorable structures allow mechanism‐based performance optimization. Herein, we firstly report a single ethylenediaminetetraacetic acid (EDTA) molecular‐level immobilized on the surface of carbon nanotube as a catalyst for transferring CO2 to CH4 with an excellent performance. This catalyst exhibits a high Faradaic efficiency of 61.6 % toward CH4, a partial current density of −16.5 mA cm−2 at a potential of −1.3 V versus reversible hydrogen electrode. Density functional theory calculations reveal that the Lewis basic COO− groups in EDTA molecule are the active sites for CO2 reduction reaction (CO2RR). The energy barrier for the generation of CO from *CO intermediate is as high as 0.52 eV, while the further protonation of *CO to *CHO follows an energetic downhill path (−1.57 eV), resulting in the high selectivity of CH4. This work makes it possible to control the product selectivity for CO2RR according to the relationship between the energy barrier of *CO intermediate and molecular structures in the future. [ABSTRACT FROM AUTHOR]

The most active catalysts so far successful in hydrogenation reduction of CO2 are mainly heterogeneous Cu‐based catalysts. The complex coordination environments and multiple active sites in heterogeneous catalysts result in low selectivity of target product, while molecular catalysts with well‐defined active sites and tailorable structures allow mechanism‐based performance optimization. Herein, we firstly report a single ethylenediaminetetraacetic acid (EDTA) molecular‐level immobilized on the surface of carbon nanotube as a catalyst for transferring CO2 to CH4 with an excellent performance. This catalyst exhibits a high Faradaic efficiency of 61.6 % toward CH4, a partial current density of −16.5 mA cm−2 at a potential of −1.3 V versus reversible hydrogen electrode. Density functional theory calculations reveal that the Lewis basic COO− groups in EDTA molecule are the active sites for CO2 reduction reaction (CO2RR). The energy barrier for the generation of CO from *CO intermediate is as high as 0.52 eV, while the further protonation of *CO to *CHO follows an energetic downhill path (−1.57 eV), resulting in the high selectivity of CH4. This work makes it possible to control the product selectivity for CO2RR according to the relationship between the energy barrier of *CO intermediate and molecular structures in the future. [ABSTRACT FROM AUTHOR]

The most active catalysts so far successful in hydrogenation reduction of CO2 are mainly heterogeneous Cu‐based catalysts. The complex coordination environments and multiple active sites in heterogeneous catalysts result in low selectivity of target product, while molecular catalysts with well‐defined active sites and tailorable structures allow mechanism‐based performance optimization. Herein, we firstly report a single ethylenediaminetetraacetic acid (EDTA) molecular‐level immobilized on the surface of carbon nanotube as a catalyst for transferring CO2 to CH4 with an excellent performance. This catalyst exhibits a high Faradaic efficiency of 61.6 % toward CH4, a partial current density of −16.5 mA cm−2 at a potential of −1.3 V versus reversible hydrogen electrode. Density functional theory calculations reveal that the Lewis basic COO− groups in EDTA molecule are the active sites for CO2 reduction reaction (CO2RR). The energy barrier for the generation of CO from *CO intermediate is as high as 0.52 eV, while the further protonation of *CO to *CHO follows an energetic downhill path (−1.57 eV), resulting in the high selectivity of CH4. This work makes it possible to control the product selectivity for CO2RR according to the relationship between the energy barrier of *CO intermediate and molecular structures in the future. [ABSTRACT FROM AUTHOR]

The most active catalysts so far successful in hydrogenation reduction of CO2 are mainly heterogeneous Cu‐based catalysts. The complex coordination environments and multiple active sites in heterogeneous catalysts result in low selectivity of target product, while molecular catalysts with well‐defined active sites and tailorable structures allow mechanism‐based performance optimization. Herein, we firstly report a single ethylenediaminetetraacetic acid (EDTA) molecular‐level immobilized on the surface of carbon nanotube as a catalyst for transferring CO2 to CH4 with an excellent performance. This catalyst exhibits a high Faradaic efficiency of 61.6 % toward CH4, a partial current density of −16.5 mA cm−2 at a potential of −1.3 V versus reversible hydrogen electrode. Density functional theory calculations reveal that the Lewis basic COO− groups in EDTA molecule are the active sites for CO2 reduction reaction (CO2RR). The energy barrier for the generation of CO from *CO intermediate is as high as 0.52 eV, while the further protonation of *CO to *CHO follows an energetic downhill path (−1.57 eV), resulting in the high selectivity of CH4. This work makes it possible to control the product selectivity for CO2RR according to the relationship between the energy barrier of *CO intermediate and molecular structures in the future. [ABSTRACT FROM AUTHOR]

Benefiting from the incorporation of foreign transition metals into the noble metal lattice, which endows altered electronic structure accompanying a downshift in the d -band center energy, the IrFe nanoalloys which supported on N-doped graphene layers (IrFe/NC) exhibit remarkable performance towards HER in alkaline media, which even surpasses that of the commercial Pt/C catalysts. Such excellent performance is originated from the modulated electronic, superior conductivity and large exposed active-site density. • The underlying HER activity of Ir has been activated and optimized. • The catalyst shows an overpotential of only 850 mV at 1000 mA cm−2, which surpasses commercial 40% Pt/C (1.17 V) in 1 M KOH. • The IrFe/NC catalyst exhibits excellent stability and displays about 100 % Faradaic yield in the whole test process. • The superior performance attributes to ultrafine alloy nanoparticles, modulated electronic structure, superior conductivity and large exposed active-site density. The exploration of electrocatalysts with high activity and durability for hydrogen evolution reaction (HER) at extremely high current densities above 500 mA cm−2 in alkaline media is the basis for large-scale industrial applications. Plain Ir possesses optimum performance for OER in alkaline electrolytes but presents a noticeable underperforming HER activity. Herein, the strategy by pyrolyzing Ir-modified metal-organic frameworks (MOFs) precursors has been employed in designing electrocatalysts consisting of IrFe nanoalloys supported on N-doped carbon layers. The catalyst requires a small overpotential of 105 mV to deliver a current density of 100 mA cm-2 in basic media, which surpasses that of commercial Ir/C and Pt/C benchmarks. Particularly, the catalyst also exhibits an extraordinary performance with low overpotential of only 850 mV at 1000 mA cm-2. The extraordinary performance originates from superior conductivity, the modulated electronic structure and large specific surface area. [ABSTRACT FROM AUTHOR]