Tuning Fe doping Co/CoOx amorphous nanofilms to enhance the hydrolytic activity towards ammonia borane

Abstract

Hydrolytic dehydrogenation of ammonia borane (AB) has attracted much attention due to its high hydrogen content and stability. Therefore, the design and construction of low-cost and high-performance catalysts for AB hydrolysis are of great significance. In this work, Co/CoFeOx-X (X is the additional content of Fe precursor) bimetallic oxide nanofilms having an amorphous structure were prepared on an (IL)/water interface for the hydrolysis of AB. Strategies including the rapid addition of metal precursors and variation of Co/Fe atom ratios were employed to induce an amorphous structure for inhibiting the rearrangement of the formed metal nuclei and optimizing the alloying effect on the IL/water interface. This ultrathin amorphous nanofilm structure can expose more metal active sites. Moreover, the electronic interaction between Fe and Co after doping Fe into the Co/CoOx nanofilms facilitates the adsorption and activation for AB and H2O molecules. As a result, the optimized Co/CoFeOx-25 catalyst exhibits excellent catalytic activity with a turnover frequency (TOF) value of 12.25 molH2·molCo–1·min–1, which is considerably higher than that of the monometallic Co/CoOx catalyst. This enhanced activity can be ascribed to the morphology advantages and the electronic effect of Fe and Co on the Co/CoFeOx-25 catalyst. This work provides a promising method to design the highly efficient non-noble metal catalysts for the hydrolysis of chemical hydrides.