We report a new synthetic strategy for preparing well-organised, spherical and mesoporous, mixed-metal, hollow-core@layered double hydroxides. Hollow-SiO@Cu Zn Mg Al-LDHs ( + + = 2.32 ± 0.
View Article and Find Full Text PDFStrain engineering has emerged as a powerful approach in steering material properties. However, the mechanism and potential limitations remain poorly understood. Here we report that subtle changes in molecular configurations can profoundly affect, conducively or adversely, the catalytic selectivity and product turnover frequencies (TOFs) of CO reduction reaction.
View Article and Find Full Text PDFSingle-atom catalysts (SACs), featuring highly uniform active sites, tunable coordination environments, and synergistic effects with support, have emerged as one of the most efficient catalysts for various reactions, particularly for electrochemical CO reduction (ECR). However, the scalability of SACs is restricted due to the limited choice of available support and problems that emerge when preparing SACs by thermal deposition. Here, an in situ reconstruction method for preparing SACs is developed with a variety of atomic sites, including nickel, cadmium, cobalt, and magnesium.
View Article and Find Full Text PDFProtonation represents a fundamental chemical process with promising applications in the fields of energy, environment, and memory devices. Probing the protonation mechanism, however, presents a formidable challenge owing to the elusiveness of intercalated protons. In this work, we utilize the atomic and electronic structure changes associated with protonation to directly image the proton intercalation pathways in α-MoO induced by UV illumination.
View Article and Find Full Text PDFUnraveling the catalyst surface structure and behavior during reactions is essential for both mechanistic understanding and performance optimization. Here we report a phenomenon of facet-dependent surface restructuring intrinsic to β-Ni(OH) catalysts during oxygen evolution reaction (OER), discovered by the correlative and characterization. The study after OER reveals β-Ni(OH) restructuring at the edge facets to form nanoporous NiO, which is Ni deficient containing Ni species.
View Article and Find Full Text PDFAlthough oxygen vacancies (Ovs) have been intensively studied in single semiconductor photocatalysts, exploration of intrinsic mechanisms and in-depth understanding of Ovs in S-scheme heterojunction photocatalysts are still limited. Herein, a novel S-scheme photocatalyst made from WO-Ov/InS with Ovs at the heterointerface is rationally designed. The microscopic environment and local electronic structure of the S-scheme heterointerface are well optimized by Ovs.
View Article and Find Full Text PDFCo-intercalation reactions make graphite a feasible anode in Ca ion batteries, yet the correlation between Ca ion intercalation behaviors and electrolyte structure remains unclear. This study, for the first time, elucidates the pivotal role of anions in modulating the Ca ion solvation structures and their subsequent intercalation into graphite. Specifically, the electrostatic interactions between Ca ion and anions govern the configurations of solvated-Ca-ion in dimethylacetamide-based electrolytes and graphite intercalation compounds.
View Article and Find Full Text PDFThe insufficient active sites and slow interfacial charge transfer of photocatalysts restrict the efficiency of CO photoreduction. The synchronized modulation of the above key issues is demanding and challenging. Herein, strain-induced strategy is developed to construct the Bi-O-bonded interface in Cu porphyrin-based monoatomic layer (PML-Cu) and BiOBr (BOB), which triggers the surface interface dual polarization of PML-Cu/BOB (PBOB).
View Article and Find Full Text PDFDesigning high-performance thermal catalysts with stable catalytic sites is an important challenge. Conventional wisdom holds that strong metal-support interactions can benefit the catalyst performance, but there is a knowledge gap in generalizing this effect across different metals. Here, we have successfully developed a generalizable strong metal-support interaction strategy guided by Tammann temperatures of materials, enabling functional oxide encapsulation of transition metal nanocatalysts.
View Article and Find Full Text PDFCatalytic NH synthesis and decomposition offer a new promising way to store and transport renewable energy in the form of NH from remote or offshore sites to industrial plants. To use NH as a hydrogen carrier, it is important to understand the catalytic functionality of NH decomposition reactions at an atomic level. Here, we report for the first time that Ru species confined in a 13X zeolite cavity display the highest specific catalytic activity of over 4000 h for the NH decomposition with a lower activation barrier, compared to most reported catalytic materials in the literature.
View Article and Find Full Text PDFLaminar membranes comprising graphene oxide (GO) and metal-organic framework (MOF) nanosheets benefit from the regular in-plane pores of MOF nanosheets and thus can support rapid water transport. However, the restacking and agglomeration of MOF nanosheets during typical vacuum filtration disturb the stacking of GO sheets, thus deteriorating the membrane selectivity. Therefore, to fabricate highly permeable MOF nanosheets/reduced GO (rGO) membranes, a two-step method is applied.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2022
The design of efficient non-noble metal catalysts for CO hydrogenation to fuels and chemicals is desired yet remains a challenge. Herein, we report that single Mo atoms with a MoN (pyrrolic) moiety enable remarkable CO adsorption and hydrogenation to CO, as predicted by density functional theory studies and evidenced by a high and stable conversion of CO reaching about 30.4 % with a CO selectivity of almost 100 % at 500 °C and very low H partial pressure.
View Article and Find Full Text PDFZeolites have found tremendous applications in the chemical industry. However, the dynamic nature of their active sites under the flow of adsorbate molecules for adsorption and catalysis is unclear, especially in operando conditions, which could be different from the as-synthesized structures. In the present study, we report a structural transformation of the adsorptive active sites in SAPO-34 zeolite by using acetone as a probe molecule under various temperatures.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2020
There is increasing interest in capturing H generated from renewables with CO to produce methanol. However, renewable hydrogen production is expensive and in limited quantity compared to CO . Excess CO and limited H in the feedstock gas is not favorable for CO hydrogenation to methanol, causing low activity and poor methanol selectivity.
View Article and Find Full Text PDFForeign transition metals are doped into the hexagonal nickel phosphide structure through a simple and facile bottom-up wet-chemical synthesis process via stabilization with oleylamine, trioctylphosphine (TOP), and trioctylphosphine oxide (TOPO): the as-prepared transition metal-doped nickel phosphide nanoparticles show a high level of doping but create no significant distortion of the crystal structure and morphology against pristine nickel phosphide nanoparticles, which exhibit excellent activity in the electrochemical oxygen evolution reaction (OER), having overpotential as small as 330 mV at 20 mA cm with a low Tafel slope value of 39 mV dec.
View Article and Find Full Text PDFThe traditional investigation of complex catalyst poisoning phenomena is in the operation level: poisonings commonly attributed to macroscopic coke deposition and particle size change, etc. Here, we demonstrate that high-resolution SXRD can reveal the structure of the organic molecule-active site complex in a 3-D environment, leading to an understanding of the poisoning mechanism at the molecular level.
View Article and Find Full Text PDFThe conversion of oxygen-rich biomass into hydrocarbon fuels requires efficient hydrodeoxygenation catalysts during the upgrading process. However, traditionally prepared CoMoS catalysts, although efficient for hydrodesulfurization, are not appropriate due to their poor activity, sulfur loss and rapid deactivation at elevated temperature. Here, we report the synthesis of MoS monolayer sheets decorated with isolated Co atoms that bond covalently to sulfur vacancies on the basal planes that, when compared with conventionally prepared samples, exhibit superior activity, selectivity and stability for the hydrodeoxygenation of 4-methylphenol to toluene.
View Article and Find Full Text PDFIt is demonstrated that light elements, including lithium and boron atoms, can take residence in the octahedral (interstitial) site of a Pd lattice by modifying the electronic properties of the metal nanoparticles, and hence the adsorptive strength of a reactant. The blocking of the sub-surface sites to H in the modified materials results in significantly higher selectivity for the partial catalytic hydrogenation of acetylene to ethylene.
View Article and Find Full Text PDFIncorporation of CdS quantum dots is shown to significantly promote photocatalytic hydrogen production from water over single-layer MoS in a remote manner via their dispersions on a carbon nanotube as a nanocomposite: the hydrogen evolution rate is found to be critically dependent on the content and structural integrity of the carbon nanotube such that the double-walled carbon nanotube shows superior H production to a single-walled carbon nanotube because the inner carbon tubules survive from the structural damage during functionalization.
View Article and Find Full Text PDFNear quantitative carbon yields of diesel-range alkanes were achieved from the hydrodeoxygenation of triglycerides over Pd/NbOPO4 under mild conditions with no catalyst deactivation: catalyst characterization and theoretical calculations suggest that the high hydrodeoxygenation activity originated from the synergistic effect of Pd and strong Lewis acidity on the unique structure of NbOPO4.
View Article and Find Full Text PDFIncorporation of Zn atoms into a nanosize Cu lattice is known to alter the electronic properties of Cu, improving catalytic performance in a number of industrially important reactions. However the structural influence of Zn on the Cu phase is not well studied. Here, we show that Cu nano-clusters modified with increasing concentration of Zn, derived from ZnO support doped with Ga(3+), can dramatically enhance their stability against metal sintering.
View Article and Find Full Text PDFSurfactant-free bimetallic Ni@Ag nanoparticles in mesoporous silica, SBA-15 prepared by simple wet co-impregnation catalyse hydrogenation of dimethyl oxalate to methyl glycolate or ethylene glycol in high yield.
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