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Efficient heterogeneous catalyst design primarily focuses on engineering the active sites or supports, often neglecting the impact of trace impurities on catalytic performance. Herein, we demonstrate that even trace amounts of sulfate (SO42-) residuals on Ru/TiO2 can totally change the CO2 reduction from methanation to reverse-water gas shift (RWGS) reaction under atmospheric pressure. We reveal that air annealing causes the trace amount of SO42- to migrate from TiO2 to Ru/TiO2 interface, leading to the significant changes in product selectivity from CH4 to CO. Detailed characterizations and DFT calculations show that the sulfate at Ru/TiO2 interface notably enhances the H transfer from Ru particles to the TiO2 support, weakening the CO intermediate activation on Ru particles and inhibiting the further hydrogenation of CO to CH4. This discovery highlights the vital role of trace impurities in CO2 hydrogenation reaction, and also provides broad implications for the design and development of more efficient and selective heterogeneous catalysts.

Internal combustion engine fueled by carbon-free hydrogen (H2-ICE) offers a promising alternative for sustainable transportation. Herein, we report a facile and universal strategy through the physical mixing of Pt catalyst with zeolites to significantly improve the catalytic performance in the selective catalytic reduction of nitrogen oxides (NOx) with H2 (H2-SCR), a process aiming at NOx removal from H2-ICE. Via the physical mixing of Pt/TiO2 with Y zeolite (Pt/TiO2 + Y), a remarkable enhancement of NOx reduction activity and N2 selectivity was simultaneously achieved. The incorporation of Y zeolite effectively captured the in-situ generated water, fostering a water-rich environment surrounding the Pt active sites. This environment weakened the NO adsorption while concurrently promoting the H2 activation, leading to the strikingly elevated H2-SCR activity and N2 selectivity on Pt/TiO2 + Y catalyst. This study provides a unique, easy and sustainable physical mixing approach to achieve proficient heterogeneous catalysis for environmental applications.

Effective synthesis and application of single-atom catalysts on supports lacking enough defects remain a significant challenge in environmental catalysis. Herein, we present a universal defect-enrichment strategy to increase the surface defects of CeO2-based supports through H2 reduction pretreatment. The Pt catalysts supported by defective CeO2-based supports, including CeO2, CeZrOx, and CeO2/Al2O3 (CA), exhibit much higher Pt dispersion and CO oxidation activity upon reduction activation compared to their counterpart catalysts without defect enrichment. Specifically, Pt is present as embedded single atoms on the CA support with enriched surface defects (CA-HD) based on which the highly active catalyst showing embedded Pt clusters (PtC) with the bottom layer of Pt atoms substituting the Ce cations in the CeO2 surface lattice can be obtained through reduction activation. Embedded PtC can better facilitate CO adsorption and promote O2 activation at PtC-CeO2 interfaces, thereby contributing to the superior low-temperature CO oxidation activity of the Pt/CA-HD catalyst after activation.

Chlorate (ClO3-) is a common water pollutant due to its gigantic scale of production, wide applications in agriculture and industry, and formation as a toxic byproduct in various water treatment processes. This work reports on the facile preparation, mechanistic elucidation, and kinetic evaluation of a bimetallic catalyst for highly active ClO3- reduction into Cl-. Under 1 atm H2 and 20 °C, PdII and RuIII were sequentially adsorbed and reduced on a powdered activated carbon support, affording Ru0-Pd0/C from scratch within only 20 min. The Pd0 particles significantly accelerated the reductive immobilization of RuIII as >55% dispersed Ru0 outside Pd0. At pH 7, Ru-Pd/C shows a substantially higher activity of ClO3- reduction (initial turnover frequency >13.9 min-1 on Ru0; rate constant at 4050 L h-1 gmetal-1) than reported catalysts (e.g., Rh/C, Ir/C, Mo-Pd/C) and the monometallic Ru/C. In particular, Ru-Pd/C accomplished the reduction of concentrated 100 mM ClO3- (turnover number > 11,970), whereas Ru/C was quickly deactivated. In the bimetallic synergy, Ru0 rapidly reduces ClO3- while Pd0 scavenges the Ru-passivating ClO2- and restores Ru0. This work demonstrates a simple and effective design for heterogeneous catalysts tailored for emerging water treatment needs.

Adding CrIII or AlIII salts into the water suspension of platinum group metal (PGM) catalysts accelerated oxyanion pollutant reduction by up to 600%. Our initial attempts of adding K2CrVIO4, K2CrVI2O7, or KCrIII(SO4)2 into Pd/C enhanced BrO3- reduction with 1 atm H2 by 6-fold. Instrument characterizations and kinetic explorations collectively confirmed the immobilization of reduced CrVI as CrIII(OH)3 on the catalyst surface. This process altered the ζ-potentials from negative to positive, thus substantially enhancing the Langmuir-Hinshelwood adsorption equilibrium constant for BrO3- onto Pd/C by 37-fold. Adding AlIII(OH)3 from alum at pH 7 achieved similar enhancements. The Cr-Pd/C and Al-Pd/C showed top-tier efficiency of catalytic performance (normalized with Pd dosage) among all the reported Pd catalysts on conventional and nanostructured support materials. The strategy of adding inert metal hydroxides works for diverse PGMs (palladium and rhodium), substrates (BrO3- and ClO3-), and support materials (carbon, alumina, and silica). This work shows a simple, inexpensive, and effective example of enhancing catalyst activity and saving PGMs for environmental applications.

Constructing single atom catalysts with fine-tuned coordination environments can be a promising strategy to achieve satisfactory catalytic performance. Herein, via a simple calcination temperature-control strategy, CeO2 supported Pt single atom catalysts with precisely controlled coordination environments are successfully fabricated. The joint experimental and theoretical analysis reveals that the Pt single atoms on Pt1/CeO2 prepared at 550 °C (Pt/CeO2-550) are mainly located at the edge sites of CeO2 with a Pt-O coordination number of ca. 5, while those prepared at 800 °C (Pt/CeO2-800) are predominantly located at distorted Ce substitution sites on CeO2 terrace with a Pt-O coordination number of ca. 4. Pt/CeO2-550 and Pt/CeO2-800 with different Pt1-CeO2 coordination environments exhibit a reversal of activity trend in CO oxidation and NH3 oxidation due to their different privileges in reactants activation and H2O desorption, suggesting that the catalytic performance of Pt single atom catalysts in different target reactions can be maximized by optimizing their local coordination structures.

Commercial Cu-exchanged small-pore SSZ-13 (Cu-SSZ-13) zeolite catalysts are highly active for the standard selective catalytic reduction (SCR) of NO with NH3. However, their activity is unexpectedly inhibited in the presence of NO2 at low temperatures. This is strikingly distinct from the NO2-accelerated NOx conversion over other typical SCR catalyst systems. Here, we combine kinetic experiments, in situ X-ray absorption spectroscopy, and density functional theory (DFT) calculations to obtain direct evidence that under reaction conditions, strong oxidation by NO2 forces Cu ions to exist mainly as CuII species (fw-Cu2+ and NH3-solvated CuII with high CNs), which impedes the mobility of Cu species. The SCR reaction occurring at these CuII sites with weak mobility shows a higher energy barrier than that of the standard SCR reaction on dynamic binuclear sites. Moreover, the NO2-involved SCR reaction tends to occur at the Brønsted acid sites (BASs) rather than the CuII sites. This work clearly explains the strikingly distinctive selective catalytic behavior in this zeolite system.

The past decade has brought tremendous progress in diagnostic and therapeutic options for cerebrovascular diseases as exemplified by the advent of thrombectomy in ischemic stroke, benefitting a steeply increasing number of stroke patients and potentially paving the way for a renaissance of neuroprotectants. Progress in basic science has been equally impressive. Based on a deeper understanding of pathomechanisms underlying cerebrovascular diseases, new therapeutic targets have been identified and novel treatment strategies such as pre- and post-conditioning methods were developed. Moreover, translationally relevant aspects are increasingly recognized in basic science studies, which is believed to increase their predictive value and the relevance of obtained findings for clinical application.This review reports key results from some of the most remarkable and encouraging achievements in neurovascular research that have been reported at the 10th International Symposium on Neuroprotection and Neurorepair. Basic science topics discussed herein focus on aspects such as neuroinflammation, extracellular vesicles, and the role of sex and age on stroke recovery. Translational reports highlighted endovascular techniques and targeted delivery methods, neurorehabilitation, advanced functional testing approaches for experimental studies, pre-and post-conditioning approaches as well as novel imaging and treatment strategies. Beyond ischemic stroke, particular emphasis was given on activities in the fields of traumatic brain injury and cerebral hemorrhage in which promising preclinical and clinical results have been reported. Although the number of neutral outcomes in clinical trials is still remarkably high when targeting cerebrovascular diseases, we begin to evidence stepwise but continuous progress towards novel treatment options. Advances in preclinical and translational research as reported herein are believed to have formed a solid foundation for this progress.

This paper mainly focuses on the application of nanostructured MoO3 materials in both energy and environmental catalysis fields. MoO3 has wide tunability in bandgap, a unique semiconducting structure, and multiple valence states. Due to the natural advantage, it can be used as a high-activity metal oxide catalyst, can serve as an excellent support material, and provide opportunities to replace noble metal catalysts, thus having broad application prospects in catalysis. Herein, we comprehensively summarize the crystal structure and properties of nanostructured MoO3 and highlight the recent significant research advancements in energy and environmental catalysis. Several current challenges and perspective research directions based on nanostructured MoO3 are also discussed.

Efficient heterogeneous catalyst design primarily focuses on engineering the active sites or supports, often neglecting the impact of trace impurities on catalytic performance. Herein, we demonstrate that even trace amounts of sulfate (SO42−) residuals on Ru/TiO2 can totally change the CO2 reduction from methanation to reverse-water gas shift (RWGS) reaction under atmospheric pressure. We reveal that air annealing causes the trace amount of SO42− to migrate from TiO2 to Ru/TiO2 interface, leading to the significant changes in product selectivity from CH4 to CO. Detailed characterizations and DFT calculations show that the sulfate at Ru/TiO2 interface notably enhances the H transfer from Ru particles to the TiO2 support, weakening the CO intermediate activation on Ru particles and inhibiting the further hydrogenation of CO to CH4. This discovery highlights the vital role of trace impurities in CO2 hydrogenation reaction, and also provides broad implications for the design and development of more efficient and selective heterogeneous catalysts. The impact of trace impurities on catalytic performance is often overlooked. Here the authors show that trace amounts of sulfate residuals on Ru/TiO2 substantially enhance hydrogen transfer from Ru particles to the TiO2 support, shifting CO2 reduction from methanation to the reverse water-gas shift reaction. [ABSTRACT FROM AUTHOR]

Catalytic oxidation of alcohols is an essential process for energy conversion, production of fine chemicals and pharmaceutical intermediates. Although it has been broadly utilized in industry, the basic understanding for catalytic alcohol oxidations at a molecular level, especially under both gas and liquid phases, is still lacking. In this paper, we systematically summarized our work on catalytic alcohol oxidation over size-controlled Pt nanoparticles. The studied alcohols included methanol, ethanol, 1-propanol, 2-propanol, and 2-butanol. The turnover rates of different alcohols on Pt nanoparticles and also the apparent activation energy in gas and liquid phase reactions were compared. The Pt nanoparticle size dependence of reaction rates and product selectivity was also carefully examined. Water showed very distinct effects for gas and liquid phase alcohol oxidations, either as an inhibitor or as a promoter depending on alcohol type and reaction phase. A deep understanding of different alcohol molecular orientations on Pt surface in gas and liquid phase reactions was established using sum-frequency generation spectroscopy analysis for in situ alcohol oxidations, as well as density functional theory calculation. This approach can not only explain the entirely different behaviors of alcohol oxidations in gas and liquid phases, but can also provide guidance for future catalyst/process design.

Alcohol oxidation reaction over platinum nanoparticles with size ranging from 2 to 8 nm deposited on mesoporous silica MCF-17 was studied in the gas and liquid phases. Among methanol, ethanol, 2- propanol, and 2-butanol oxidations, the turnover frequency increased as the nanoparticle size became large in both reaction phases. The activation energy in the gas phase was higher than that in the liquid phase. Water coadsorption decreased the turnover rate of all the gas and liquid phase oxidations except for the gas-phase 2-butanol case, while a certain amount of water promoted 2-propanol oxidation in the liquid phase. Sum frequency generation vibrational spectroscopy study and DFT calculation revealed that the alcohol molecules pack horizontally on the metal surface in low concentration and stand up in high concentration, which affects the dissociation of β-hydrogen of the alcohol as the critical step in alcohol oxidation. (Graph Presented).