Understanding and Tuning the Effects of HO on Catalytic CO and CO Hydrogenation.

Catalytic CO (CO and CO) hydrogenation to valued chemicals is one of the promising approaches to address challenges in energy, environment, and climate change. HO is an inevitable side product in these reactions, where its existence and effect are often ignored. In fact, HO significantly influences the catalytic active centers, reaction mechanism, and catalytic performance, preventing us from a definitive and deep understanding on the structure-performance relationship of the authentic catalysts.

Computational Design of Single-atom Modified Ti-MOFs for Photocatalytic CO Reduction to C Chemicals.

In this work, density functional theory (DFT) calculations were conducted to investigate a series of transition metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ru, Rh, Pd, Ag, Hf, Ta, Os, Ir, and Pt) as single-atom components introduced into Ti-BPDC (BPDC=2,2'-bipyridine-5,5'-dicarboxylic acid) as catalysts (M/Ti-BPDC) for the photocatalytic reduction of CO. The results show that Fe/Ti-BPDC is the most active candidate for CO reduction to HCOOH due to its small limiting potential (-0.40 V).

Stabilizing CoC with HO and K promoter for CO hydrogenation to C hydrocarbons.

The decomposition of cobalt carbide (CoC) to metallic cobalt in CO hydrogenation results in a notable drop in the selectivity of valued C products, and the stabilization of CoC remains a grand challenge. Here, we report an in situ synthesized K-CoC catalyst, and the selectivity of C hydrocarbons in CO hydrogenation achieves 67.3% at 300°C, 3.

Metal single-site catalyst design for electrocatalytic production of hydrogen peroxide at industrial-relevant currents.

Direct hydrogen peroxide (HO) electrosynthesis via the two-electron oxygen reduction reaction is a sustainable alternative to the traditional energy-intensive anthraquinone technology. However, high-performance and scalable electrocatalysts with industrial-relevant production rates remain to be challenging, partially due to insufficient atomic level understanding in catalyst design. Here we utilize theoretical approaches to identify transition-metal single-site catalysts for two-electron oxygen reduction using the *OOH binding energy as a descriptor.

Mechanistic Insight into Hydrocarbon Synthesis via CO Hydrogenation on χ-FeC Catalysts.

Converting CO into value-added chemicals and fuels is one of the promising approaches to alleviate CO emissions, reduce the dependence on nonrenewable energy resources, and minimize the negative environmental effect of fossil fuels. This work used density functional theory (DFT) calculations combined with microkinetic modeling to provide fundamental insight into the mechanisms of CO hydrogenation to hydrocarbons over the iron carbide catalyst, with a focus on understanding the energetically favorable pathways and kinetic controlling factors for selective hydrocarbon production. The crystal orbital Hamiltonian population analysis demonstrated that the transition states associated with O-H bond formation steps within the path are less stable than those of C-H bond formation, accounting for the observed higher barriers in O-H bond formation from DFT.

Selective electroreduction of CO to acetone by single copper atoms anchored on N-doped porous carbon.

Efficient electroreduction of CO to multi-carbon products is a challenging reaction because of the high energy barriers for CO activation and C-C coupling, which can be tuned by designing the metal centers and coordination environments of catalysts. Here, we design single atom copper encapsulated on N-doped porous carbon (Cu-SA/NPC) catalysts for reducing CO to multi-carbon products. Acetone is identified as the major product with a Faradaic efficiency of 36.

Computational and experimental identification of strong synergy of the Fe/ZnO catalyst in promoting acetic acid synthesis from CH and CO.

DFT calculations have identified reaction pathways for acetic acid synthesis from CO and CH on ZnO, Cu/ZnO and Fe/ZnO surfaces. Fe/ZnO exhibits strong synergy in facilitating CH activation, dissociation and C-C coupling. Thus, the surface acetate formation is significantly enhanced.

Recent Advances in Carbon Dioxide Hydrogenation to Methanol via Heterogeneous Catalysis.

The utilization of fossil fuels has enabled an unprecedented era of prosperity and advancement of well-being for human society. However, the associated increase in anthropogenic carbon dioxide (CO) emissions can negatively affect global temperatures and ocean acidity. Moreover, fossil fuels are a limited resource and their depletion will ultimately force one to seek alternative carbon sources to maintain a sustainable economy.

Tandem Reactions of CO Reduction and Ethane Aromatization.

Aromatization of light alkanes is of great interest because this can expand the raw materials used to produce aromatics to include fractions of natural gas that are readily available and inexpensive. Combining CO reduction with ethane dehydrogenation and aromatization can also mitigate CO emissions. A one-step process that can produce liquid aromatics from the reactions of CO and ethane using phosphorus (P)- and gallium (Ga)-modified ZSM-5 has been evaluated at 873 K and atmospheric pressure.

Mechanistic Insight into Propylene Epoxidation with HO over Titanium Silicalite-1: Effects of Zeolite Confinement and Solvent.

Density functional theory (DFT) calculations were performed to investigate the effects of zeolite confinement and solvent on propylene epoxidation with HO over the titanium silicalite-1 (TS-1) catalyst. The 144T and 143T cluster models containing typical 10MR channels of TS-1 were constructed to represent the tripodal(2I) and Ti/defect sites. It was found that the confinement of the zeolite pore channel not only impacts the adsorption stability of guest molecules but also alters reaction barriers, as compared to the results obtained based on small cluster models.

DFT insight into the effect of potassium on the adsorption, activation and dissociation of CO over Fe-based catalysts.

Catalytic conversion of CO2 including hydrogenation has attracted great attention as a method for chemical fixation of CO2 in combination with other techniques such as CO2 capture and storage. Potassium is a well-known promotor for many industrial catalytic processes such as in Fischer-Tropsch synthesis. In this work, we performed density functional theory (DFT) calculations to investigate the effect of potassium on the adsorption, activation, and dissociation of CO2 over Fe(100), Fe5C2(510) and Fe3O4(111) surfaces.

Computational Prediction of Metal Organic Frameworks Suitable for Molecular Infiltration as a Route to Development of Conductive Materials.

The development of metal organic frameworks (MOFs) with high porosity, large surface area, and good electrical properties would offer opportunities for producing functionalized porous materials suitable for energy storage, conversion, and utilization. Realizing these applications remains challenging because of the limited numbers of electrically conductive porous MOFs that are known. We apply density functional theory (DFT) to assess a large number of potentially electrically conductive MOFs generated by infiltrating known materials with conjugated and redox-active 7,7,8,8-tetracyanquinododimethane (TCNQ) molecules.

Low Pressure CO2 Hydrogenation to Methanol over Gold Nanoparticles Activated on a CeO(x)/TiO2 Interface.

Capture and recycling of CO2 into valuable chemicals such as alcohols could help mitigate its emissions into the atmosphere. Due to its inert nature, the activation of CO2 is a critical step in improving the overall reaction kinetics during its chemical conversion. Although pure gold is an inert noble metal and cannot catalyze hydrogenation reactions, it can be activated when deposited as nanoparticles on the appropriate oxide support.

Poisoning effect of adsorbed CO during CO2 electroreduction on late transition metals.

Copper cathodes, at sufficiently negative potentials, are selective for hydrocarbon production during the electrochemical reduction of carbon dioxide. Other metals, such as Pt, Fe, Ni and Co, produce low to zero hydrocarbons. We employ density functional theory to examine the coverage of reaction intermediates under CO2 electroreduction conditions.

Selectivity of CO(2) reduction on copper electrodes: the role of the kinetics of elementary steps.

On the right path: Based on DFT calculations (incorporating the role of water solvation) of the activation barriers of elementary steps, a new path that leads to methane and ethylene for CO(2) electroreduction on Cu(111) was identified. Methane formation proceeds through reduction of CO to COH (path II, see picture), which leads to CH(x) species that can produce both methane and ethylene, as observed experimentally.

A computational investigation of ring-shift isomerization of sym-octahydrophenanthrene to sym-octahydroanthracene catalyzed by acidic zeolites.

The ring-shift isomerization of sym-octahydrophenanthrene (sym-OHP) to sym-octahydroanthracene (sym-OHA) catalyzed by acidic zeolites (Mordenite (MOR) and Faujasite (FAU)) was investigated by the ONIOM(DFT:UFF) and DFT approaches. A "five-membered ring" mechanism through carbocation rearrangement via 1-2 migration was proved to be kinetically favored over a "six-membered ring" mechanism through Friedel-Crafts reactions. Computational studies based on the "five-membered ring" mechanism demonstrate that a decreasing Brønsted acid site strength from Al-H-MOR to Ga-H-MOR to B-H-MOR reduces the catalytic activity.