Photothermocatalytic Removal of CO and Formaldehyde with Excellent Water Vapor Stability over Dual‐Functional Copper Loading on TiO₂ Synthesized via Flame Spray Pyrolysis

Abstract

Photothermocatalytic (PTC) oxidation is a high‐efficient, low‐temperature, and green approach to eliminate the air pollutant, but its application is drastically restricted by lack of low‐cost, active, and superior water‐resistance catalysts. Herein, the influence of bifunctional copper components on TiO2 is experimentally and theoretically investigated to optimize PTC efficiency for the CO and HCHO oxidation via flame spray pyrolysis. Both the abundant lattice doping and highly dispersed nanocluster modification of hybrid CuO x remarkably enhance charge separation, maintain a dynamic Cu+/Cu2+ balance, and decrease oxygen vacancy formation energy. The satisfactory PTC CO and HCHO oxidation on the CuO x −TiO2 samples is mainly attributed to higher lattice oxygen activity and less reaction intermediates under irradiation. In addition, the essential synthesis parameters, such as the increasing precursor flux, are assessed to further enhance the PTC performance. Interestingly, photocatalysis effectively removes the surface H2O or hydroxyl group of catalysts, which is responsible for the excellent water vapor stability in the lean CO PTC oxidation.

CuO Quantum Dots Supported by SrTiO3 Perovskite Using the Flame Spray Pyrolysis Method: Enhanced Activity and Excellent Thermal Resistance for Catalytic Combustion of CO and CH4

“…To reduce the pollution emission, there have been mounting concerns about the elimination of carbon monoxide (CO) and methane (CH 4 ). , The catalytic combustion can completely convert lean CO and CH 4 into carbon dioxide (CO 2 ) and water (H 2 O) under mild conditions, which is an efficient and environmentally friendly technique and possesses an outstanding application prospect. − However, the application of the platinum-group metal catalysts shows disadvantages of, for example, high cost, obvious sintering and inactivation at high temperature, and difficult large-quantity production. Therefore, it is essential to develop more economical catalysts utilizing less critical raw materials. , …”

Deep Insight into the Mechanism of Catalytic Combustion of CO and CH4 over SrTi1–xBxO3 (B = Co, Fe, Mn, Ni, and Cu) Perovskite via Flame Spray Pyrolysis

“…26 The Coulombic interactions of transition metals are corrected by the GGA + U method, with self-consistent U values of 3.2 for Ti, 6.2 for Co, 4.0 for Mn, 4.2 eV for Fe, and 5.0 eV for Cu, respectively. 11,27,28 Especially, all methane calculations are performed by the DFT-D method to correct for van der Waals interactions. The convergence criteria for the maximum interatomic force, total energy, and displacement tolerances are 0.03 eV/Å, 1.0 × 10 −5 eV/atom, and 0.001 Å, respectively.…”

“…In this work, all density functional theory (DFT) calculations are conducted by the CASTEP (Cambridge Serial Total Energy Package) codes, employing the generalized gradient approximation (GGA) and Perdew–Wang (PW91) exchange-correlation energy. , The cutoff energy of 400 eV and the k-point meshes of 3 × 3 × 1 are used for the SrTiO 3 surface slab . The Coulombic interactions of transition metals are corrected by the GGA + U method, with self-consistent U values of 3.2 for Ti, 6.2 for Co, 4.0 for Mn, 4.2 eV for Fe, and 5.0 eV for Cu, respectively. ,, Especially, all methane calculations are performed by the DFT-D method to correct for van der Waals interactions. The convergence criteria for the maximum interatomic force, total energy, and displacement tolerances are 0.03 eV/Å, 1.0 × 10 –5 eV/atom, and 0.001 Å, respectively.…”