Although considerable progress has been made in carbon dioxide (CO) hydrogenation to various C chemicals, it is still a great challenge to synthesize value-added products with two or more carbons, such as gasoline, directly from CO because of the extreme inertness of CO and a high C-C coupling barrier. Here we present a bifunctional catalyst composed of reducible indium oxides (InO) and zeolites that yields a high selectivity to gasoline-range hydrocarbons (78.6%) with a very low methane selectivity (1%). The oxygen vacancies on the InO surfaces activate CO and hydrogen to form methanol, and C-C coupling subsequently occurs inside zeolite pores to produce gasoline-range hydrocarbons with a high octane number. The proximity of these two components plays a crucial role in suppressing the undesired reverse water gas shift reaction and giving a high selectivity for gasoline-range hydrocarbons. Moreover, the pellet catalyst exhibits a much better performance during an industry-relevant test, which suggests promising prospects for industrial applications.

Direct conversion of carbon dioxide (CO2) into lower olefins (C2 =–C4 =), generally referring to ethylene, propylene, and butylene, is highly attractive as a sustainable production route for its great significance in greenhouse gas control and fossil fuel substitution, but such a route always tends to be low in selectivity toward olefins. Here we present a bifunctional catalysis process that offers C2 =–C4 = selectivity as high as 80% and C2–C4 selectivity around 93% at more than 35% CO2 conversion. This is achieved by a bifunctional catalyst composed of indium–zirconium composite oxide and SAPO-34 zeolite, which is responsible for CO2 activation and selective C–C coupling, respectively. We demonstrate that both the precise control of oxygen vacancies on the oxide surface and the integration manner of the components are crucial in the direct production of lower olefins from CO2 hydrogenation. No obvious deactivation is observed over 150 h, indicating a promising potential for industrial application.

The (TiO2)n clusters and their anions for n = 1-4 have been studied with coupled cluster theory [CCSD(T)] and density functional theory (DFT). For n > 1, numerous conformations are located for both the neutral and anionic clusters, and their relative energies are calculated at both the DFT and CCSD(T) levels. The CCSD(T) energies are extrapolated to the complete basis set limit for the monomer and dimer and calculated up to the triple-zeta level for the trimer and tetramer. The adiabatic and vertical electron detachment energies of the anionic clusters to the ground and first excited states of the neutral clusters are calculated at both levels and compared with the experimental results. The comparison allows for the definitive assignment of the ground-state structures of the anionic clusters. Anions of the dimer and tetramer are found to have very closely lying conformations within 2 kcal/mol at the CCSD(T) level, whereas that of the trimer does not. In addition, accurate clustering energies and heats of formation are calculated for the neutral clusters and compared with the available experimental data. Estimates of the titanium-oxygen bond energies show that they are stronger than the group VIB transition metal-oxygen bonds except for tungsten. The atomization energies of these clusters display much stronger basis set dependence than the clustering energies. This allows the calculation of more accurate heats of formation for larger clusters on the basis of calculated clustering energies.

The structural, energetic, and electronic properties of gold ions adsorbed methanol, Au(3)(+)-(CH(3)OH)(m) (m = 1-3) and Au(5)(+)-(CH(3)OH)(m) (m = 1-5), have been investigated using density functional theory (DFT) within a generalized gradient approximation (GGA). The geometric parameters, vibrational frequencies, adsorption energies, and Mulliken charges are used to analyze the interactions between Au(3,5)(+) clusters and methanol molecules. The present calculations show that more than one methanol molecule can be adsorbed onto small clusters of gold ions and that this adsorption is different from that of single-molecule absorption. The red shift of the C-O stretching frequency decreases as the number of methanol molecules, m, increases or as gold cluster size increases. The positive charge on Au(3,5)(+) and coordination number of the adsorption sites on the gold cluster are the dominant factors responsible for the strength of the interactions. We obtained C-O stretching frequencies in Au(1,2)(+)-(CH(3)OH) complexes that are below 931 cm(-1), which provides theoretical evidence for the experimental observation by Dietrich et al. [J. Chem. Phys. 2000, 112, 752].

CO electroreduction is a promising technique for satisfying both renewable energy storage and a negative carbon cycle. However, it remains a challenge to convert CO into C2 products with high efficiency and selectivity. Herein, we report a nitrogen-doped ordered cylindrical mesoporous carbon as a robust metal-free catalyst for CO electroreduction, enabling the efficient production of ethanol with nearly 100 % selectivity and high faradaic efficiency of 77 % at -0.56 V versus the reversible hydrogen electrode. Experiments and density functional theory calculations demonstrate that the synergetic effect of the nitrogen heteroatoms and the cylindrical channel configurations facilitate the dimerization of key CO* intermediates and the subsequent proton-electron transfers, resulting in superior electrocatalytic performance for synthesizing ethanol from CO .

The structures and properties of transition metal oxide (TMO) clusters of the group VIB metals, (MO(3))(n) (M = Cr, Mo, W; n = 1-6), have been studied with density functional theory (DFT) methods. Geometry optimizations and frequency calculations were carried out at the local and nonlocal DFT levels with polarized valence double-zeta quality basis sets, and final energies were calculated at nonlocal DFT levels with polarized valence triple-zeta quality basis sets at the local and nonlocal DFT geometries. Effective core potentials were used to treat the transition metal atoms. Two types of clusters were investigated, the ring and the chain, with the ring being lower in energy. Large ring structures (n > 3) were shown to be fluxional in their out of plane deformations. Long chain structures (n > 3) of (CrO(3))(n) were predicted to be weakly bound complexes of the smaller clusters at the nonlocal DFT levels. For M(6)O(18), two additional isomers were also studied, the cage and the inverted cage. The relative stability of the different conformations of M(6)O(18) depends on the transition metal as well as the level of theory. Normalized and differential clustering energies of the ring structures were calculated and were shown to vary with respect to the cluster size. Brönsted basicities and Lewis acidities based on a fluoride affinity scale were also calculated. The Brönsted basicities as well as the Lewis acidities depend on the size of the cluster and the site to which the proton or the fluoride anion binds. These clusters are fairly weak Brönsted bases with gas phase basicities comparable to those of H(2)O and NH(3). The clusters are, however, very strong Lewis acids and many of them are stronger than strong Lewis acids such as SbF(5). Brönsted acidities of M(6)O(19)H(2) and M(6)O(18)FH were calculated for M = Mo and W and these compounds were shown to be very strong acids in the gas phase. The acid/base properties of these TMO clusters are expected to play important roles in their catalytic activities.

Renewable energy-driven methanol synthesis from CO2 and green hydrogen is a viable and key process in both the “methanol economy” and “liquid sunshine” visions. Recently, In2O3-based catalysts have shown great promise in overcoming the disadvantages of traditional Cu-based catalysts. Here, we report a successful case of theory-guided rational design of a much higher performance In2O3 nanocatalyst. Density functional theory calculations of CO2 hydrogenation pathways over stable facets of cubic and hexagonal In2O3 predict the hexagonal In2O3(104) surface to have far superior catalytic performance. This promotes the synthesis and evaluation of In2O3 in pure phases with different morphologies. Confirming our theoretical prediction, a novel hexagonal In2O3 nanomaterial with high proportion of the exposed {104} surface exhibits the highest activity and methanol selectivity with high catalytic stability. The synergy between theory and experiment proves highly effective in the rational design and experimental realization of oxide catalysts for industry-relevant reactions.

Conversion of carbon dioxide (CO ) into fuels and chemicals by electroreduction has attracted significant interest, although it suffers from a large overpotential and low selectivity. A Pd-Sn alloy electrocatalyst was developed for the exclusive conversion of CO into formic acid in an aqueous solution. This catalyst showed a nearly perfect faradaic efficiency toward formic acid formation at the very low overpotential of -0.26 V, where both CO formation and hydrogen evolution were completely suppressed. Density functional theory (DFT) calculations suggested that the formation of the key reaction intermediate HCOO* as well as the product formic acid was the most favorable over the Pd-Sn alloy catalyst surface with an atomic composition of PdSnO , consistent with experiments.