Advanced surface engineering of Al2O3 support accelerates H2 activation and H spillover for Ni-catalyzed hydrogen storage enabling integration with water electrolysis

초록

Supported nickel catalysts have increasingly replaced noble metal catalysts in H2-involved catalysis, for which extensive engineering of catalyst components induces reaction-favorable Ni properties, particularly for Ni/Al2O3. Although Ni–support interactions considerably alter geometric and electronic Ni states, fundamental insights into how a support surface can be effectively reformed for desired Ni characters remain not fully covered. Here we utilize a coupled surface-modification strategy of Al2O3 hydroxylation and alkylsilane grafting to modulate homolytic H2 adsorption and H spillover for converting an aromatic liquid organic hydrogen carrier. The approach when coupled forms the on-top Ni0 and interfacial Niδ+ species at Si–O–Al domains localized on Al2O3. The former Ni species supply weakly-adsorbed H species participating in H spillover, while the latter in cooperation with nearby surface hydroxyls enhances hydrogen turnover rate. As a result of cooperative interplay of these two Ni species, the designed Ni catalysts outperform the counterparts prepared by single modification and exhibit excellent recyclability under dry hydrogenation conditions. The demonstrated H2 activation and H spillover can work, if a H-spillover carrier is supplemented, under humid conditions pertinent to H2 supplied from H2O electrolysis.

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