Modulating Tit_2gOrbital Occupancy in a Cu/TiO₂Composite for Selective Photocatalytic CO₂Reduction to CO

Abstract

The electronic structure of composites plays a critical role in photocatalytic conversion, whereas it is challenging to modulate the orbital for an efficient catalyst. Herein, we regulated the t 2g orbital occupancy state of Ti to realize efficient CO 2 conversion by adjusting the amount of photo-deposited Cu in the Cu/ TiO 2 composite. For the optimal sample, considerable electrons transfer from the Cu d orbital to the Ti t 2g orbital, as proven by X-ray absorption spectroscopy. The Raman spectra results also corroborate the electron enrichment on the Ti t 2g orbital. Further theoretical calculations suggested that the orbital energy of the Ti 3d orbital in TiO 2 is declined, contributing to accepting Cu 3d electrons. As a result, the Cu/TiO 2 composite exhibited an extremely high selectivity of 95.9 % for CO, and the productivity was 15.27 μmol g À 1 h À 1 , which is almost 6 times that of the original TiO 2 . Our work provides a strategy for designing efficient photocatalysis as a function of orbital regulation.

S‐Scheme Co9S8@Cd0.8Zn0.2S‐DETA Hierarchical Nanocages Bearing Organic CO2 Activators for Photocatalytic Syngas Production

“…[22,23] This indicates the Co(bpy) 3 2+ /CoS@CdZnS-DETA system is thermodynamically favorable for the CO 2 conversion reaction. Afterword, protonation of COOH * to produce CO * requires a very low free energy barrier change of 0.05 eV, [44] which may explain the sole production of CO in the CO 2 reduction reaction. The downhill free energy profile suggests that the conversion from CO * to CO is easier and more spontaneous assisted with acquisition of the light-induced electron.…”

Copper-Sulfur-Nitrogen Cluster Providing a Local Proton for Efficient Carbon Dioxide Photoreduction

“…This is possibly due to the nonradiative quenching that was enhanced by the protonated N, demonstrating that the photogenerated charge recombination is inhibited to a certain extent in the Cu6-NH cluster. 12 Likewise, it could be observed that the tailing of the fluorescence lifetime curve of Cu6-NH became more pronounced compared with that for Cu6-N, as shown in Supplementary Fig. 29.…”

“…[4][5][6][7] Unlike the widely reported systems that require additional noble-metal-based photosensitizers and/or electron donors of organic bases, the key challenge with the artificial system lies mainly in the design of a single-component photocatalyst with suitable band structures and catalytic active centers for directly converting CO2 and H2O under solar energy, similar to the case in natural photosynthesis. [8][9][10][11] Thus far, researchers have mainly employed inorganic materials and organic conjugated polymers, such as TiO2, 12,13 ZnIn2S4, 14,15 and g-C3N4, 16,17 for the development of photocatalytic semiconductors. Few single-component photocatalysts are capable of realizing effective and highly selectively CO2 photoreduction.…”

“…6 In particular, among the various non-noble-metal-based organic-inorganic hybrid materials, Cu-based materials are the most promising earthabundant metal catalysts that can efficiently convert CO2 into valuable chemicals. 12,[24][25][26] As emerging organic-inorganic crystalline materials, ligand-protected copper nanoclusters (NCs) are attracting widespread interest, attributed to their well-defined structures comprising an external organic layer and a metal core. [27][28][29][30] The subnanoscale metal core composed of a certain number of Cu atoms is essential for the evolution of the aggregation of single atoms into nanoparticles, and it accounts for the unexpected catalytic properties of Cu NCs.…”

Guest‐Induced Multilevel Charge Transport Strategy for Developing Metal‐Organic Frameworks to Boost Photocatalytic CO2 Reduction

“…From the Tauc plot, the Eg values of the MOFs were determined to be 2.62 and 2.69 eV, which are favorable for the transition of photogenerated charge during photocatalysis. [ 42 − 45 ] In order to determine the exact valence band (VB) and conduction band (CB) positions of BPAN ‐Co‐ 1 and BPAN ‐Co‐ 2, the valence band X‐ray photoelectron spectra (VB‐XPS) were acquired as shown in Figure 2c,d. The VB potentials of BPAN ‐Co‐ 1 and BPAN ‐Co‐ 2, determined by the tangent intercept of the state density at the Fermi edge, were 1.15 and 0.88 eV, respectively.…”