too strong of a metal-support interaction would trigger Ostwald ripening, whereas too weak of that would lead to particle migration and coalescence. Therefore, the metal-support binding energy serves as a descriptor to predict the growth rates of supported NPs in this case. [14] Strong metal-support interaction (SMSI) is a special form of interaction that is typically observed between metal NPs and reducible supports. [15][16][17] In 1978, Tauster et al. first discovered that the chemisorption abilities of TiO 2 -supported Group VIII noble metals toward small gas molecules, such as CO and H 2 , suddenly disappeared after a reduction treatment at 500 °C. [15] In this case, the term SMSI was proposed to describe this phenomenon that was once believed to be caused by the electronic perturbation due to the formation of PtTi bond. [16,[18][19][20] Later, subsequent investigations confirmed the encapsulation of metal NPs by migrated support species. [21][22][23][24] In 1986, Sakellson et al. provided direct evidences of the SMSI in Rh-TiO 2 using extended X-ray absorption fine structure spectroscopy (EXAFS)-the RhTi bond formed between Rh NPs and TiO 2 support was apparently shorter than that in RhTi intermetallic compounds due to the cationic nature of Ti n+ in TiO 2 . [25] This highlights the meaning of "strong" in "SMSI". On that occasion, Tauster emphasized that the SMSI should be referred to as the formation of such strong interfacial metalmetal bonds rather than its subsequent consequences. [17] However, considering the difficulty in detecting the relatively small amounts of interfacial bonds in supported metal NPs, SMSI is still identified by the apparent change of physicochemical behaviors including encapsulation, loss of chemisorption ability, etc.Later, similar phenomena were observed when other reducible metal oxides were used as the supports including CeO 2 , [26,27] Nb 2 O 5 , [28,29] etc. Moreover, such a reduction-induced SMSI can be eliminated after oxidation treatment at elevated temperatures. Recently, the SMSI has been observed between some new components beyond the typical Group VIII noble metals and reducible metal oxide supports. [30][31][32] The development of advanced material characterization technologies, in situ high-resolution transmission electron microscopy (HRTEM) for example, [33][34][35][36] has also brought new insights into understanding SMSI behaviors. More importantly, owing to its intriguing behaviors, SMSI brings about new principles for designing and modulating advanced heterogeneous catalysts toward thermocatalysis and electrocatalysis. [27,[37][38][39] Meanwhile, it should also be noted that the concept of SMSI has been usedStrong metal-support interaction (SMSI) in supported metal catalysts, typically accompanied by the formation of encapsulation layers over metal nanoparticles, has drawn intense research attention owing to a variety of intriguing behaviors. In particular, recent years have witnessed enormous progress in constructing SMSI between novel components as well as...

Tailoring the interfacial interaction between metal species and supports in supported electrocatalysts is of great importance for enhanced electrocatalytic performance. Herein, a highly active interface was engineered in S-doped graphitic carbon nitride (SGCN)-supported Pt heterostructured electrocatalysts toward fast oxygen reduction reaction (ORR). The coordination and electronic structure of Pt species is modulated with enhanced Pt–N bonding by S doping, which induces electron deficiency in adjacent C and N atoms and hence reinforces the metal–support interaction. The optimal 20Pt/SGCN-550 electrocatalyst exhibits excellent ORR performance with a half-wave potential of 0.91 V and a mass activity of 0.68 A mgPt –1, substantially surpassing that of 20Pt/GCN and commercial Pt/C. Besides, the 20Pt/SGCN-550 electrocatalyst achieves decent durability due to the superb stability of SGCN and the strong confinement effect at the interface. This work not only advances the development of robust ORR electrocatalysts but also offers a strategy to engineer heterostructured electrocatalysts with tunable interface chemistry toward various catalytic applications.

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The sluggish kinetics of hydrogen oxidation reaction (HOR) is one of the critical challenges for anion exchange membrane fuel cells. Here, we report epitaxial growth of Ir nanoclusters (<2 nm) on a MoS2 surface (Ir/MoS2) and optimize the alkaline HOR activity via tailoring interfacial charge transfer between Ir clusters and MoS2. The electron transfer from MoS2 to Ir clusters can effectively prevent the oxidation of Ir clusters, which is not the case for carbon‐supported Ir nanoclusters (Ir/C) synthesized using the same method. Moreover, the HOR performance of the Ir/MoS2 can be further optimized by tuning the hydrogen binding energy (HBE) via a precise annealing treatment. A substantial exchange current density of 1.28 mA cmECSA−2 is achieved in the alkaline medium, which is ∼10 times over that of Ir/C. The HOR mass‐specific activity of Ir/MoS2 heterostructure is as high as 182 mA mgIr−1. The experimental results and density functional theory calculations reveal that the significant improved HOR activity is attributed to the decreased HBE, which highlights epitaxial growth is an effective way for boosting catalytic activity of heterostructured catalysts.