Engineering Bimodal Oxygen Vacancies and Pt to Boost the Activity Toward Water Dissociation

Abstract

Water dissociation is the rate‐limiting step of several energy‐related reactions due to the high energy barrier required for breaking the oxygen–hydrogen bond. In this work, a bimodal oxygen vacancy (VO) catalysis strategy is adopted to boost the efficient water dissociation on Pt nanoparticles. The single facet‐exposed TiO2 surface and NiOx nanocluster possess two modes of VO different from each other. In ammonia borane hydrolysis, the highest catalytic activity among Pt‐based materials is achieved with the turnover frequency of 618 min−1 under alkaline‐free conditions at 298 K. Theoretical simulation and characterization analyses reveal that the bimodal VO significantly promotes the water dissociation in two ways. First, an ensemble‐inducing effect of Pt and VO in TiO2 drives the activation of water molecules. Second, an electron promoter effect induced by the electron transfer from VO in NiOx to Pt further enhances the ability of Pt to dissociate water and ammonia borane. This insight into bimodal VO catalysis establishes a new avenue to rationally design heterogeneous catalytic materials in the energy chemistry field.

Crystal facet effects of platinum single-atom catalysts in hydrolytic dehydrogenation of ammonia borane

“…Additionally, the turnover frequency (TOF) of Pt 1 /Co 3 O 4 -c in AB hydrolytic dehydrogenation was about 6035 mol H 2 mol Pt −1 min −1 , which was higher than that of Pt 1 /Co 3 O 4 -t (2143 mol H2 mol Pt −1 min −1 ) and Pt 1 /Co 3 O 4 -o (1719 mol H 2 mol Pt −1 min −1 ) and outperformed almost all supported Pt-based catalysts ever reported (Fig. 3b, e and Table S2†), 10,25,27,28,32–34,41–49 confirming that both the addition of Pt single-atoms and the interaction between Pt and Co 3 O 4 exposed surfaces affected the catalytic activity.…”

“…25,26 Thus, discovering efficient catalysts to release H 2 from AB is very essential and being widely studied. 27,28 As previous research suggests, catalysts designed based on the Co 3 O 4 nanomaterials, provide preeminent catalytic performance in hydrolytic dehydrogenation of AB, [29][30][31] especially Pt/Co 3 O 4 catalysts. 10,[32][33][34] To promote the catalytic activity of the catalysts, we synthesize three kinds of Co 3 O 4 supports with different exposed facets to anchor atomically dispersed Pt species.…”

“…As shown in Fig. S5, S2 †), 10,25,27,28,[32][33][34][41][42][43][44][45][46][47][48][49] conrming that both the addition of Pt single-atoms and the interaction between Pt and Co 3 O 4 exposed surfaces affected the catalytic activity. Furthermore, to investigate the kinetics of AB hydrolytic dehydrogenation, experiments were conducted at different temperatures with Pt 1 /Co 3 O 4 -x (x ¼ c, t, o) catalysts (Fig.…”

Engineering Nonprecious Metal Oxides Electrocatalysts for Two‐Electron Water Oxidation to H2O2

“…Defect engineering is another method to regulate the electronic property of the underlying catalyst, which has a significant effect on the catalytic activity with the ability to moderate the surface/interface charge distribution and so on. [106][107][108] Among various defects, oxygen vacancy is the most favorable and wellstudied defect which can not only regulate the oxidation states of metal centers but also moderate the absorption energy of intermediates as well as introduce new active sites into the catalysts, collectively promoting their activities. [109][110][111] Yu and Zhao previously coated CaSnO 3 precursor in carbon fibers (CFs) via electrospinning and the modulation of oxygen vacancy was achieved by annealing CaSnO 3 under N 2 atmosphere (Figure 10a).…”

Promoting water dissociation for efficient solar driven CO2 electroreduction via improving hydroxyl adsorption

“…As a universal intrinsic defect, oxygen vacancy (V O ) in metal oxide is commonly considered to modify metal active site, while the role of V O itself is neglected generally [26][27][28][29][30][31] . Yet V O possesses strong oxygen affinity and fast interaction with water, which indicates it can serve as promising active site in tuning the energy barrier of water dissociation 32,33 . Thus, it is anticipated that constructing V O might enable enhancing CO 2 performance by relieving the effect of sluggish H 2 O dissociation and optimizing active sites, which is of great significance in offering a new avenue in efficient electrocatalyst exploration for CO 2 RR and deeper understanding the role of water dissociation in the whole reaction.…”