Embedding Single Pd Atoms on NiGa Intermetallic Surfaces for Efficient and Selective Alkyne Hydrogenation.

Catalytic removal of alkynes is essential in industry for producing polymer-grade alkenes from steam cracking processes. Non-noble Ni-based catalysts hold promise as effective alternatives to industrial Pd-based catalysts but suffer from low activity. Here we report embedding of single-atom Pd onto the NiGa intermetallic surface with replacing Ga atoms via a well-defined synthesis strategy to design Pd-NiGa catalyst for alkyne semi-hydrogenation.

Remote Activation of H-H Bonds by Platinum in Dilute Alloy Catalysts.

With heterogeneous catalysts, chemical promotion takes place at their surfaces. Even in the case of single-atom alloys, where small quantities of a reactive metal are dispersed within the main host, it is assumed that both elements are exposed and available to bond with the reactants. Here, we show, on the basis of X-ray absorption spectroscopy data, that in alloy catalysts made from Pt highly diluted in Cu the Pt atoms are located at the inner interface between the metal nanoparticles and the silica support instead.

Atomic Design of Alkyne Semihydrogenation Catalysts via Active Learning.

Alkyne hydrogenation on palladium-based catalysts modified with silver is currently used in industry to eliminate trace amounts of alkynes in alkenes produced from steam cracking and alkane dehydrogenation processes. Intensive efforts have been devoted to designing an alternative catalyst for improvement, especially in terms of selectivity and catalyst cost, which is still far away from that as expected. Here, we describe an atomic design of a high-performance Ni-based intermetallic catalyst aided by active machine learning combined with density functional theory calculations.

Synthesis of piperidines and pyridine from furfural over a surface single-atom alloy RuCo catalyst.

The sustainable production of value-added N-heterocycles from available biomass allows to reduce the reliance on fossil resources and creates possibilities for economically and ecologically improved synthesis of fine and bulk chemicals. Herein, we present a unique RuCo/HAP surface single-atom alloy (SSAA) catalyst, which enables a new type of transformation from the bio-based platform chemical furfural to give N-heterocyclic piperidine. In the presence of NH and H, the desired product is formed under mild conditions with a yield up to 93%.

Catalyzing Generation and Stabilization of Oxygen Vacancies on CeO Nanorods by Pt Nanoclusters as Nanozymes for Catalytic Therapy.

Although CeO nanomaterials have been widely explored as nanozymes for catalytic therapy, they still suffer from relatively low activities. Herein, the catalyzing generation and stabilization of oxygen vacancies on CeO nanorods by Pt nanoclusters via H gas reduction under mild temperature (350 °C) to obtain Pt/CeO , which can serve as a highly efficient nanozyme for catalytic cancer therapy, is reported. The deposited Pt on CeO by the atomic layer deposition technique not only can serve as the catalyst to generate oxygen vacancies under mild temperature reduction through the hydrogen spillover effect, but also can stabilize the generated oxygen vacancies.

Thermal management of natural gas production from coke oven gas by optimizing catalyst distribution and operation conditions.

In this work, 3D particle-resolved CFD simulations have been performed to investigate the thermal effects of natural gas production from coke oven gas. The catalyst packing structures with uniform, gradient rise and gradient descent distribution and the operating conditions of pressure, wall temperature, inlet temperature and feed velocity are optimized for reduced hot spot temperature. The simulation results show that compared with packing structures with uniform distribution and gradient descent distribution, the gradient rise distribution could effectively reduce the hot spot temperature without affecting the reactor performance in the reactor with upflow reactants feeding, of which the reactor bed temperature rise is 37 K.

Ruthenium/TiO -Catalyzed Hydrogenolysis of Polyethylene Terephthalate: Reaction Pathways Dominated by Coordination Environment.

Polyethylene terephthalate (PET) hydrogenolysis can produce benzene, toluene, and xylene (BTX), where the selectivity control is challenging. We report a reaction pathway dictated by the Ru coordination environment by examining the binding geometries of adsorbates on differently coordinated Ru centers and their evolution during PET hydrogenolysis. A BTX yield of 77 % was obtained using a Ru/TiO with a Ru coordination number of ca.

In situ identification of surface sites in Cu-Pt bimetallic catalysts: Gas-induced metal segregation.

The effect of gases on the surface composition of Cu-Pt bimetallic catalysts has been tested by in situ infrared (IR) and x-ray absorption spectroscopies. Diffusion of Pt atoms within the Cu-Pt nanoparticles was observed both in vacuum and under gaseous atmospheres. Vacuum IR spectra of CO adsorbed on CuPt/SBA-15 catalysts (x = 0-∞) at 125 K showed no bonding on Pt regardless of Pt content, but reversible Pt segregation to the surface was seen with the high-Pt-content (x ≥ 0.

Increasing the Distance of Adjacent Palladium Atoms for Configuration Matching in Selective Hydrogenation.

Precisely tailoring the distance between adjacent metal sites to match adsorption configurations of key species for the targeted reaction pathway is a great challenge in heterogeneous catalysis. Here, we report a proof-of-concept study on the atomically sites-tailored pathway in Pd-catalyzed acetylene hydrogenation, i.e.

Mechanism driven design of trimer NiSb site delivering superior hydrogenation selectivity to ethylene.

Mechanism driven catalyst design with atomically uniform ensemble sites is an important yet challenging issue in heterogeneous catalysis associated with breaking the activity-selectivity trade-off. Herein, a trimer NiSb site in NiSb intermetallic featuring superior selectivity is elaborated for acetylene semi-hydrogenation via a theoretical guidance with a precise synthesis strategy. The trimer NiSb site in NiSb intermetallic is predicted to endow acetylene reactant with an adequately but not excessively strong σ-adsorption mode while ethylene product with a weak π-adsorption one, where such compromise delivers higher ethylene formation rate.

Mechanistic insights into acid-affected hydrogenolysis of glycerol to 1,3-propanediol over an Ir-Re/SiO catalyst.

Glycerol hydrogenolysis to 1,3-propanediol is identified to follow the dehydration-hydrogenation pathway with the rate-determining step (RDS) of H* + OH* → HO* over an IrRe catalyst. The positive effects of solid acids are elucidated to originate from the reduced energy barrier of the RDS by H protons, while the negative ones of liquid acids are from excessively strong adsorption of anions.

A flexible and disposable electrochemical sensor for the evaluation of arsenic levels: A new and efficient method for the batch fabrication of chemically modified electrodes.

In this study, a novel flexible and disposable electrochemical sensor was fabricated through the straightforward laser-induced synthesis of catalytic Au nanoparticles (AuNPs)@LIG composite for the square wave stripping voltammetry (SWASV) determination of arsenic in soil. In this process, polyimide and a metal precursor (PI-MP) were transformed to three-dimensional porous LIG and AuNPs through the graphitization, photoreduction and thermal reduction of laser ablation. To our knowledge, this is the first time that laser-induced PI-MP was employed to fabricate chemically modified electrodes on a large scale for arsenic determination.

Interfacial-confined coordination to single-atom nanotherapeutics.

Pursuing and developing effective methodologies to construct highly active catalytic sites to maximize the atomic and energy efficiency by material engineering are attractive. Relative to the tremendous researches of carbon-based single atom systems, the construction of bio-applicable single atom materials is still in its infancy. Herein, we propose a facile and general interfacial-confined coordination strategy to construct high-quality single-atom nanotherapeutic agent with Fe single atoms being anchored on defective carbon dots confined in a biocompatible mesoporous silica nanoreactor.

Molecular-level insights into the electronic effects in platinum-catalyzed carbon monoxide oxidation.

A molecular-level understanding of how the electronic structure of metal center tunes the catalytic behaviors remains a grand challenge in heterogeneous catalysis. Herein, we report an unconventional kinetics strategy for bridging the microscopic metal electronic structure and the macroscopic steady-state rate for CO oxidation over Pt catalysts. X-ray absorption and photoelectron spectroscopy as well as electron paramagnetic resonance investigations unambiguously reveal the tunable Pt electronic structures with well-designed carbon support surface chemistry.

Surface enrichment and diffusion enabling gradient-doping and coating of Ni-rich cathode toward Li-ion batteries.

Critical barriers to layered Ni-rich cathode commercialisation include their rapid capacity fading and thermal runaway from crystal disintegration and their interfacial instability. Structure combines surface modification is the ultimate choice to overcome these. Here, a synchronous gradient Al-doped and LiAlO-coated LiNiCoO cathode is designed and prepared by using an oxalate-assisted deposition and subsequent thermally driven diffusion method.

Construction of highly accessible single Co site catalyst for glucose detection.

The development of high-performance glucose sensors is an urgent need, especially for diabetes mellitus diagnosis. However, the glucose monitoring is conventionally operated in an invasive finger-prick manner and their noninvasive alternatives largely suffered from the relatively poor sensitivity, selectivity, and stability, resulted from the lack of robust and efficient catalysts. In this paper, we design a concave shaped nitrogen-doped carbon framework embellished with single Co site catalyst (Co SSC) by selectively controlling the etching rate on different facet of carbon substrate, which is beneficial to the diffusion and contact of analyte.

Role of C-Defective Sites in CO Adsorption over ϵ-Fe C and η-Fe C Fischer-Tropsch Catalysts.

Herein, we report the crucial importance of C-defective sites on the CO adsorption over ϵ-Fe C and η-Fe C Fischer-Tropsch catalysts via systematic DFT calculations. The simulated XRD and Wulff construction show the significant differences in their equilibrium shapes and most exposed surfaces. It is observed that the ϵ-Fe C exposes a high proportion (89 %) of facets (1 1) with similar structure to that of η-Fe C (011) which has been proved to be the active surface of CO activation.

Gold catalysts containing interstitial carbon atoms boost hydrogenation activity.

Supported gold nanoparticles are emerging catalysts for heterogeneous catalytic reactions, including selective hydrogenation. The traditionally used supports such as silica do not favor the heterolytic dissociation of hydrogen on the surface of gold, thus limiting its hydrogenation activity. Here we use gold catalyst particles partially embedded in the pore walls of mesoporous carbon with carbon atoms occupying interstitial sites in the gold lattice.

Unleash electron transfer in C-H functionalization by mesoporous carbon-supported palladium interstitial catalysts.

The functionalization of otherwise unreactive C-H bonds adds a new dimension to synthetic chemistry, yielding useful molecules for a range of applications. Arylation has emerged as an increasingly viable strategy for functionalization of heteroarenes which constitute an important class of structural moieties for organic materials. However, direct bisarylation of heteroarenes to enable aryl-heteroaryl-aryl bond formation remains a formidable challenge, due to the strong coordination between heteroatom of N or S and transitional metals.

Adsorption Site Regulation to Guide Atomic Design of Ni-Ga Catalysts for Acetylene Semi-Hydrogenation.

Atomic regulation of metal catalysts has emerged as an intriguing yet challenging strategy to boost product selectivity. Here, we report a density functional theory-guided atomic design strategy for the fabrication of a NiGa intermetallic catalyst with completely isolated Ni sites to optimize acetylene semi-hydrogenation processes. Such Ni sites show not only preferential acetylene π-adsorption, but also enhanced ethylene desorption.

Eye-Readable Detection and Oxidation of CO with a Platinum-Based Catalyst and a Binuclear Rhodium Complex.

Toxic gases that are colorless and odorless, such as CO, are a major environmental concern and require early detection to prevent serious toxicological effects. In this study, a unique system (Pt/HMSs-BRC) was fabricated by combining a catalyst (Pt/hollow mesoporous silica spheres, Pt/HMSs) with a silica gel containing an adsorbed chromogenic probe (binuclear rhodium complex, BRC). The process is a simple method to prepare well-dispersed and uniform Pt nanoparticles.

Relationship between biochars' porosity and adsorption of three neutral herbicides from water.

The porous biochars have exhibited good adsorption to many organic pollutants, but the relationship between biochars' porosity and their adsorption capacity is not clear at the moment. In this work, six biochars were produced from different feedstocks and under different pyrolysis conditions, and used for adsorption of three neutral herbicides from water. The results demonstrated that the adsorption capacity was dominated by the mesopore (1.