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Exploring durable electrocatalysts with high activity for oxygen evolution reaction (OER) in acidic media is of paramount importance for H 2 production via polymer electrolyte membrane electrolyzers, yet it remains urgently challenging. Herein, we report a synergistic strategy of Rh doping and surface oxygen vacancies to precisely regulate unconventional OER reaction path via the Ru–O–Rh active sites of Rh-RuO 2 , simultaneously boosting intrinsic activity and stability. The stabilized low-valent catalyst exhibits a remarkable performance, with an overpotential of 161 mV at 10 mA cm −2 and activity retention of 99.2% exceeding 700 h at 50 mA cm −2 . Quasi in situ/operando characterizations demonstrate the recurrence of reversible oxygen species under working potentials for enhanced activity and durability. It is theoretically revealed that Rh-RuO 2 passes through a more optimal reaction path of lattice oxygen mediated mechanism-oxygen vacancy site mechanism induced by the synergistic interaction of defects and Ru–O–Rh active sites with the rate-determining step of *O formation, breaking the barrier limitation (*OOH) of the traditional adsorption evolution mechanism. Exploring highly active and durable Ru-based electrocatalysts for acidic water oxidation is challenging. Here authors reported an ion-exchange adsorption strategy to regulate oxygen vacancies and Rh dopant, with a corresponding fundamental investigation on the lattice oxygen oxidation and the oxygen vacancy site.

The strong metal-support interaction (SMSI) has long been studied in heterogonous catalysis on account of its importance in stabilizing active metals and tuning catalytic performance. As a dynamic process taking place at the metal-support interface, the SMSI is closely related to the metal surface properties which are usually affected by the size of metal nanoparticles (NPs). In this work we report the discovery of a size effect on classical SMSI in Au/TiO 2 catalyst where larger Au particles are more prone to be encapsulated than smaller ones. A thermodynamic equilibrium model was established to describe this phenomenon. According to this finding, the catalytic performance of Au/TiO 2 catalyst with uneven size distribution can be improved by selectively encapsulating the large Au NPs in a hydrogenation reaction. This work not only brings in-depth understanding of the SMSI phenomenon and its formation mechanism, but also provides an alternative approach to refine catalyst performance. Strong metal-support interaction (SMSI) is critical in determining the catalytic performance of supported metal catalysts. Here the authors report a phenomenon of size-dependent classical SMSI in Au/TiO 2 catalyst where larger Au particles are more prone to be encapsulated than smaller ones.

In heterogeneous catalysis catalyst activation is often observed during the reaction process, which is mostly attributed to the induction by reactants. In this work we report that surface structure of molybdenum nitride (MoN x ) catalyst exhibits a high dependency on the partial pressure or concentration of reaction products i.e., CO and H 2 O in reverse water gas-shift reaction (RWGS) (CO 2 :H 2  = 1:3) but not reactants of CO 2 and H 2 . Molybdenum oxide (MoO x ) overlayers formed by oxidation with H 2 O are observed at reaction pressure below 10 mbar or with low partial pressure of CO/H 2 O products, while CO-induced surface carbonization happens at reaction pressure above 100 mbar and with high partial pressure of CO/H 2 O products. The reaction products induce restructuring of MoN x surface into more active molybdenum carbide (MoC x ) to increase the reaction rate and make for higher partial pressure CO, which in turn promote further surface carbonization of MoN x . We refer to this as the positive feedback between catalytic activity and catalyst activation in RWGS, which should be widely present in heterogeneous catalysis. Catalyst activation commonly occurs during reactions. This study demonstrates that the surface’s active structure in nitride catalysts during the reverse water gas-shift reaction varies with the partial pressure of reaction products, resulting in enhanced catalytic activity through positive feedback between catalytic activity and the evolution of MoNx’s active structure.

Charge separation is crucial for increasing the activity of semiconductor-based photocatalysts, especially in water splitting reactions. Here we show, using monoclinic bismuth vanadate crystal as a model photocatalyst, that efficient charge separation can be achieved on different crystal facets, as evidenced by the reduction reaction with photogenerated electrons and oxidation reaction with photogenerated holes, which take place separately on the {010} and {110} facets under photo-irradiation. Based on this finding, the reduction and oxidation cocatalysts are selectively deposited on the {010} and {110} facets respectively, resulting in much higher activity in both photocatalytic and photoelectrocatalytic water oxidation reactions, compared with the photocatalyst with randomly distributed cocatalysts. These results show that the photogenrated electrons and holes can be separated between the different facets of semiconductor crystals. This finding may be useful in semiconductor physics and chemistry to construct highly efficient solar energy conversion systems. Charge separation determines the efficiency of semiconductor-based photocatalysts. Here Li et al . show that, in BiVO4, photogenerated electrons and holes accumulate on different crystal facets and the targeted deposition of cocatalysts increases the efficiency of photocatalytic water oxidation.

Although considerable progress has been made in direct synthesis gas (syngas) conversion to light olefins (C₂⁼−C₄⁼) via Fischer-Tropsch synthesis (FTS), the wide product distribution remains a challenge, with a theoretical limit of only 58% for C₂–C₄ hydrocarbons. We present a process that reaches C₂⁼−C₄⁼ selectivity as high as 80% and C₂–C₄ 94% at carbon monoxide (CO) conversion of 17%. This is enabled by a bifunctional catalyst affording two types of active sites with complementary properties. The partially reduced oxide surface (ZnCrOx) activates CO and H₂, and C–C coupling is subsequently manipulated within the confined acidic pores of zeolites. No obvious deactivation is observed within 110 hours. Furthermore, this composite catalyst and the process may allow use of coal- and biomass-derived syngas with a low H₂/CO ratio.

Producing valuable chemicals like ethylene via catalytic carbon monoxide conversion is an important nonpetroleum route. Here we demonstrate an electrochemical route for highly efficient synthesis of multicarbon (C 2+ ) chemicals from CO. We achieve a C 2+ partial current density as high as 4.35 ± 0.07 A cm −2 at a low cell voltage of 2.78 ± 0.01 V over a grain boundary-rich Cu nanoparticle catalyst in an alkaline membrane electrode assembly (MEA) electrolyzer, with a C 2+ Faradaic efficiency of 87 ± 1% and a CO conversion of 85 ± 3%. Operando Raman spectroscopy and density functional theory calculations reveal that the grain boundaries of Cu nanoparticles facilitate CO adsorption and C − C coupling, thus rationalizing a qualitative trend between C 2+ production and grain boundary density. A scale-up demonstration using an electrolyzer stack with five 100 cm 2 MEAs achieves high C 2+ and ethylene formation rates of 118.9 mmol min −1 and 1.2 L min −1 , respectively, at a total current of 400 A (4 A cm −2 ) with a C 2+ Faradaic efficiency of 64%. Producing valuable chemicals like ethylene via catalytic CO conversion is an important nonpetroleum route. Here, authors demonstrate high-rate electrosynthesis of multicarbon chemicals via CO electrolysis, with a multicarbon product partial current density of 4.35 A cm −2 at a cell voltage of 2.78 V.

Charge separation is a critical process for achieving high photocatalytic efficiency, and ferroelectrics hold significant potential for facilitating effective charge separation. However, few studies have demonstrated substantial photocatalytic activity in these materials. In this study, we demonstrate that in ferroelectric PbTiO 3 , surface Ti vacancy defects near the positively polarized facets impede photocatalytic performance by trapping electrons and inducing their recombination. To tackle this issue, we selectively grew SrTiO 3 nanolayers on the polarized facets PbTiO 3 , effectively mitigating interface Ti defects. This modification establishes a efficient electron transfer pathway at the interface between the positively polarized facets and the cocatalyst, extending the electron lifetime from 50 microseconds to the millisecond scale and significantly increasing electron participation in water-splitting reactions. Consequently, the apparent quantum yield for overall water splitting achieves the highest values reported to date for ferroelectric photocatalytic materials. This work provides an effective strategy for designing advanced ferroelectric photocatalytic systems. Ferroelectrics, which exhibit excellent charge separation ability, suffer from poor photocatalytic activity. The authors unveil the limitations in charge extraction and offer strategies to design high-performance photocatalysts by eliminating surface defects.

ZnCrO x oxides coupled with zeolites (OXZEO) allow direct conversion of syngas into light olefins, while active sites in the composite oxides remain elusive. Herein, we find that ZnO particles physically mixed with ZnCr 2 O 4 spinel particles can be well dispersed onto the spinel surfaces by treatment in syngas and through a reduction-evaporation-anchoring mechanism, forming monodispersed ZnO x species with uniform thickness or dimension on ZnCr 2 O 4 up to a dispersion threshold ZnO loading of 16.0 wt% (ZnCr 2 O 4 @ZnO x ). A linear correlation between CO conversion and surface ZnO loading clearly confirms that the ZnO x overlayer on ZnCr 2 O 4 acts as the active structure for the syngas conversion, which can efficiently activate both H 2 and CO. The obtained ZnCr 2 O 4 @ZnO x catalyst combined with SAPO-34 zeolite achieves excellent catalytic performance with 64% CO conversion and 75% light olefins selectivity among all hydrocarbons. Moreover, the ZnO x overlayer is effectively anchored on the ZnCr 2 O 4 spinel, which inhibits Zn loss during the reaction and demonstrates high stability over 100 hours. Thus, a significant interface confinement effect is present between the spinel surface and the ZnO x overlayer, which helps to stabilize ZnO x active structure and enhance the catalytic performance. Identifying active sites on oxide catalysts is often challenging. Here, the authors introduce a syngas-induced dispersion method to anchor ZnO species onto ZnCr 2 O 4 , forming monodispersed ZnO x active sites that enhance catalytic performance in direct syngas conversion to light olefins.

Transition metal tellurides (TMTs) have been ideal materials for exploring exotic properties in condensed-matter physics, chemistry and materials science 1 – 3 . Although TMT nanosheets have been produced by top-down exfoliation, their scale is below the gram level and requires a long processing time, restricting their effective application from laboratory to market 4 – 8 . We report the fast and scalable synthesis of a wide variety of MTe 2 (M = Nb, Mo, W, Ta, Ti) nanosheets by the solid lithiation of bulk MTe 2 within 10 min and their subsequent hydrolysis within seconds. Using NbTe 2 as a representative, we produced more than a hundred grams (108 g) of NbTe 2 nanosheets with 3.2 nm mean thickness, 6.2 µm mean lateral size and a high yield (>80%). Several interesting quantum phenomena, such as quantum oscillations and giant magnetoresistance, were observed that are generally restricted to highly crystalline MTe 2 nanosheets. The TMT nanosheets also perform well as electrocatalysts for lithium–oxygen batteries and electrodes for microsupercapacitors (MSCs). Moreover, this synthesis method is efficient for preparing alloyed telluride, selenide and sulfide nanosheets. Our work opens new opportunities for the universal and scalable synthesis of TMT nanosheets for exploring new quantum phenomena, potential applications and commercialization. Fast and scalable synthesis of a variety of transition metal telluride nanosheets by solid lithiation and hydrolysis is demonstrated and several interesting quantum phenomena were observed, such as quantum oscillations and giant magnetoresistance.

Molybdenum supported on zeolites has been extensively studied as a catalyst for methane dehydroaromatization. Despite significant progress, the actual intermediates and particularly the first C-C bond formation have not yet been elucidated. Herein we report evolution of methyl radicals during non-oxidative methane activation over molybdenum single sites, which leads selectively to value-added chemicals. Operando X-ray absorption spectroscopy and online synchrotron vacuum ultraviolet photoionization mass spectroscopy in combination with electron microscopy and density functional theory calculations reveal the essential role of molybdenum single sites in the generation of methyl radicals and that the formation rate of methyl radicals is linearly correlated with the number of molybdenum single sites. Methyl radicals transform to ethane in the gas phase, which readily dehydrogenates to ethylene in the absence of zeolites. This is essentially similar to the reaction pathway over the previously reported SiO 2 lattice-confined single site iron catalyst. However, the availability of a zeolite, either in a physical mixture or as a support, directs the subsequent reaction pathway towards aromatization within the zeolite confined pores, resulting in benzene as the dominant hydrocarbon product. The findings reveal that methyl radical chemistry could be a general feature for metal single site catalysis regardless of the support (either zeolites MCM-22 and ZSM-5 or SiO 2 ) whereas the reaction over aggregated molybdenum carbide nanoparticles likely facilitates carbon deposition through surface C-C coupling. These findings allow furthering the fundamental insights into non-oxidative methane conversion to value-added chemicals. Understanding of the direct methane conversion mechanism is essential for further development of efficient catalysts. Here, authors demonstrate a general methyl radical chemistry for metal single site catalysis regardless of the support (either zeolite or SiO 2 ) in non-oxidative methane activation.