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• A 20-fold increase of catalytic activity via engineering the Pt-carbon interactions. • The electron transfer and interfacial bonding vary with the carbon support. • Pt/p-CNF shows the highest Pt binding energy with the least Pt-O-C linkages. • n EWG /n EDG is identified as a good descriptor of Pt/carbon catalyst. Understanding the metal-support interactions in heterogeneous catalysis is critical yet complicated to tailor-design the catalysts with desirable properties. Exemplified with Pt-catalyzed ammonia borane (AB) hydrolysis, a dramatic increase of 20 folds in the catalytic activity is achieved by engineering the Pt-carbon interactions via adopting four different carbon materials (AC, CNT, f-CNF and p-CNF) as the catalyst supports. Multiple characterization techniques reveal that the Pt-carbon electronic interactions, including electron transfer and interfacial bonding, are deemed to be mainly responsible for the remarkable enhancement in the hydrogen generation rate. The molar ratio of electron-withdrawing group to electron-donating group (n EWG /n EDG) is further identified as a descriptor of catalyst in terms of Pt binding energy, which exhibits an almost linear relationship with the catalytic activity. Moreover, a comparison of Pt catalyst pre-treatments, i.e., H 2 and AB reduction as well as Ar calcination, suggests that the Pt-O-C linkages within the Pt-carbon interactions are highly stable yet inferior to this reaction. As a result, combining the merits of the highest Pt binding energy as well as the minimum Pt-O-C linkages, the Pt/p-CNF delivers the highest catalytic activity. The insights presented here could shed new lights on the nature of Pt-carbon interactions, which could be extended to the design and manipulation of other metal-carbon catalysts. [ABSTRACT FROM AUTHOR]

• The PDDA and PVP co-functionalized CNT has been developed to support Pt catalyst. • A combined kinetics analysis, DFT calculations with multiple characterizations is conducted. • The co-functionalization improves the quantity (N i) and quality (TOF i) of Pt active sites. • The catalyst exhibits significantly enhanced H 2 generation activity and durability. Decorating the catalyst support with organic moieties to integrate multiple functionalities into metal particles offers a unique platform to promote the catalytic performance. Here, we report a mechanism-driven strategy to functionalize CNT with dual polymers, endowing the supported Pt catalyst with simultaneously enhanced hydrogen generation activity and durability. Kinetics analysis, multiple characterization and DFT calculations reveal that the PDDA acts as electron-acceptor to capture electrons from the Pt particles toward strengthened adsorption of reactants, while the PVP acts as structure-directing agent to induce the catalyst morphology evolution with a preferential exposure of Pt(1 1 1) active sites. Such electronic and geometric synergy by co-functionalizing PDDA and PVP gives rise to a 3-fold increase in the hydrogen generation activity, together with remarkably improved catalytic durability due to the suppressed adsorption of B(OH) 4 − over the Pt(1 1 1). The strategy reported here might shed new lights on establishing the functionalization protocols to design carbon supported metal catalysts with the targeted properties. [ABSTRACT FROM AUTHOR]

Increasing the utilization efficiency of noble metals by the synergy with less expensive metals is an important yet challenging issue in heterogeneous catalysis. Herein, exemplified with Pt-catalyzed hydrolytic dehydrogenation of ammonia borane, partial substitution of the Pt catalysts by over 11 times less expensive Ru is studied to obtain highly efficient and cost-effective Pt-based catalysts. It is observed that the Pt-Ru bimetallic catalysts, especially Pt 0.5 Ru 0.5 /CNT, deliver higher hydrogen generation activity and durability than the Pt/CNT and Ru/CNT catalysts, indicating a remarkable Pt-Ru synergy. The underlying nature of this synergy is elucidated by combining kinetic and isotopic analyses with multiple techniques such as HAADF-STEM, EDX, XRD, H 2 -TPR, HRTEM, XPS and ICP-AES. The appropriate activation energy and entropy of activation for the reaction are mainly responsible for the highly active Pt 0.5 Ru 0.5 /CNT catalyst, and a volcano-shaped relationship for the reactivity of these five catalysts as a function of entropy of activation is proposed. The insights revealed here might guide the rational design of catalysts for this reaction, and the methodology could be extended to unravel the nature of other bi- or multi-metallic catalysts. [ABSTRACT FROM AUTHOR]