Engineering catalytic sites at the atomic level provides an opportunity to understand the catalyst’s active sites, which is vital to the development of improved catalysts. Here we show a reliable and tunable polyoxometalate template-based synthetic strategy to atomically engineer metal doping sites onto metallic 1T-MoS 2 , using Anderson-type polyoxometalates as precursors. Benefiting from engineering nickel and oxygen atoms, the optimized electrocatalyst shows great enhancement in the hydrogen evolution reaction with a positive onset potential of ~ 0 V and a low overpotential of −46 mV in alkaline electrolyte, comparable to platinum-based catalysts. First-principles calculations reveal co-doping nickel and oxygen into 1T-MoS 2 assists the process of water dissociation and hydrogen generation from their intermediate states. This research will expand on the ability to improve the activities of various catalysts by precisely engineering atomic activation sites to achieve significant electronic modulations and improve atomic utilization efficiencies.

1T-MoS 2 and single-atom modified analogues represent a highly promising class of low-cost catalysts for hydrogen evolution reaction (HER). However, the role of single atoms, either as active species or promoters, remains vague despite its essentiality toward more efficient HER. In this work, we report the unambiguous identification of Ni single atom as key active sites in the basal plane of 1T-MoS 2 (Ni@1T-MoS 2) that result in efficient HER performance. The intermediate structure of this Ni active site under catalytic conditions was captured by in situ X-ray absorption spectroscopy, where a reversible metallic Ni species (Ni 0) is observed in alkaline conditions whereas Ni remains in its local structure under acidic conditions. These insights provide crucial mechanistic understanding of Ni@1T-MoS 2 HER electrocatalysts and suggest that the understanding gained from such in situ studies is necessary toward the development of highly efficient single-atom decorated 1T-MoS 2 electrocatalysts.

Closing the anthropogenic carbon cycle by converting CO 2 into reusable chemicals is an attractive solution to mitigate rising concentrations of CO 2 in the atmosphere. Herein, we prepared Ni metal catalysts ranging in sizef rom single atoms to over 100 nm and distributed them across Ndoped carbon substrates whichw ere obtained from converted zeolitic imidazolate frameworks (ZIF). The results show variance in CO 2 reduction performance with variance in Ni metal size.N is ingle atoms demonstrate as uperior Faradaic efficiency (FE) for CO selectivity (ca. 97 %a tÀ0.8 Vv s. RHE), while results for 4.1 nm Ni nanoparticles are slightly lower (ca. 93 %). Further increase the Ni particle sizet o 37.2 nm allows the H 2 evolution reaction (HER) to compete with the CO 2 reduction reaction (CO 2 RR). The FE towards CO production decreases to under 30 %a nd HER efficiency increase to over 70 %. These results showasize-dependent CO 2 reduction for various sizes of Ni metal catalysts.

Renewable electricity-driven water splitting provides a pathway to manufacturing hydrogen as a promising alternative to fossil fuels. A typical water electrolysis device is comprised of a cathodic hydrogen evolution reaction...

Closing the anthropogenic carbon cycle by converting CO 2 into reusable chemicals is an attractive solution to mitigate rising concentrations of CO 2 in the atmosphere. Herein, we prepared Ni metal catalysts ranging in sizef rom single atoms to over 100 nm and distributed them across Ndoped carbon substrates whichw ere obtained from converted zeolitic imidazolate frameworks (ZIF). The results show variance in CO 2 reduction performance with variance in Ni metal size.N is ingle atoms demonstrate as uperior Faradaic efficiency (FE) for CO selectivity (ca. 97 %a tÀ0.8 Vv s. RHE), while results for 4.1 nm Ni nanoparticles are slightly lower (ca. 93 %). Further increase the Ni particle sizet o 37.2 nm allows the H 2 evolution reaction (HER) to compete with the CO 2 reduction reaction (CO 2 RR). The FE towards CO production decreases to under 30 %a nd HER efficiency increase to over 70 %. These results showasize-dependent CO 2 reduction for various sizes of Ni metal catalysts.