Developing high-performance electrocatalysts toward hydrogen evolution reaction is important for clean and sustainable hydrogen energy, yet still challenging. Herein, we report a single-atom strategy to construct excellent metal-organic frameworks (MOFs) hydrogen evolution reaction electrocatalyst (NiRu0.13-BDC) by introducing atomically dispersed Ru. Significantly, the obtained NiRu0.13-BDC exhibits outstanding hydrogen evolution activity in all pH, especially with a low overpotential of 36 mV at a current density of 10 mA cm−2 in 1 M phosphate buffered saline solution, which is comparable to commercial Pt/C. X-ray absorption fine structures and the density functional theory calculations reveal that introducing Ru single-atom can modulate electronic structure of metal center in the MOF, leading to the optimization of binding strength for H2O and H*, and the enhancement of HER performance. This work establishes single-atom strategy as an efficient approach to modulate electronic structure of MOFs for catalyst design.

Motivated by in silico predictions that Co,Rh, and Ir dopants would lead to low overpotentials to improve OER activity of Ni-based hydroxides,wereport here an experimental confirmation on the altered OER activities for as eries of metals (Mo,W ,F e, Ru, Co,Rh, Ir) doped into g-NiOOH. The in situ electrical conductivity for metal doped g-NiOOH correlates well with the trend in enhanced OER activities. Density functional theory (DFT) calculations were used to rationalizethe in situ conductivity of the key intermediate states of metal doped g-NiOOH during OER. The simultaneous increase of OER activity with intermediate conductivity was later rationalized by their intrinsic connections to the double exchange (DE) interaction between adjacent metal ions with various do rbital occupancies,s erving as an indicator for the key metal-oxoradical character,and an effective descriptor for the mechanistic evaluation and theoretical guidance in design and screening of efficient OER catalysts.

Biomass conversion and biorefinery provide a feasible and novel way to release the increasingly serious energy crisis and environmental deterioration. 2,5-furandicarboxylic acid (FDCA) has received increasing attention as a significant...

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Accurately regulating the selectivity of the oxygen reduction reaction (ORR) is crucial to renewable energy storage and utilization, but challenging. A flexible alteration of ORR pathways on atomically dispersed Zn sites towards high selectivity ORR can be achieved by tailoring the coordination environment of the catalytic centers. The atomically dispersed Zn catalysts with unique O-and C-coordination structure (ZnO 3 C) or N-coordination structure (ZnN 4 ) can be prepared by varying the functional groups of corresponding MOF precursors. The coordination environment of as-prepared atomically dispersed Zn catalysts was confirmed by X-ray absorption fine structure (XAFs). Notably, the ZnN 4 catalyst processes a 4 e À ORR pathway to generate H 2 O. However, controllably tailoring the coordination environment of atomically dispersed Zn sites, ZnO 3 C catalyst processes a 2 e À ORR pathway to generate H 2 O 2 with a near zero overpotential and high selectivity in 0.1 M KOH. Calculations reveal that decreased electron density around Zn in ZnO 3 C lowers the d-band center of Zn, thus changing the intermediate adsorption and contributing to the high selectivity towards 2 e À ORR.

Single-atom catalysts represent a unique catalytic system with high atomic utilization and tunable reaction pathway. Despite current successes in their optimization and tailoring through structural and synthetic innovations, there is a lack of dynamic modulation approach for the single-atom catalysis. Inspired by the electrostatic interaction within specific natural enzymes, here we show the performance of model single-atom catalysts anchored on two-dimensional atomic crystals can be systematically and efficiently tuned by oriented external electric fields. Superior electrocatalytic performance have been achieved in single-atom catalysts under electrostatic modulations. Theoretical investigations suggest a universal “onsite electrostatic polarization” mechanism, in which electrostatic fields significantly polarize charge distributions at the single-atom sites and alter the kinetics of the rate determining steps, leading to boosted reaction performances. Such field-induced on-site polarization offers a unique strategy for simulating the catalytic processes in natural enzyme systems with quantitative, precise and dynamic external electric fields.

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