Highly Dispersed Pt Nanoparticle-Doped Mesoporous ZnO Photocatalysts for Promoting Photoconversion of CO₂ to Methanol

Abstract

Photoreduction of CO 2 is considered a challenge due to the lack of effective photocatalysts with wide-spectrum absorption, active charge separation dynamically, and CO 2 adsorption. Herein, mesoporous Pt/ZnO nanocomposites with different Pt percentages (0.5–2%) have been fabricated using the sol–gel process in the presence of a template for CO 2 photoreduction during visible-light exposure. Pt nanoparticles (NPs) deposited onto mesoporous ZnO with a considerable surface area can effectively promote charge mobility. The mesoporous 1.5% Pt/ZnO nanocomposite exhibits an optimal CH 3 OH yield (668 μmol g –1 ), which is 18.5-fold larger than that of mesoporous ZnO (36 μmol g –1 ). The most photoactive material was the 1.5% Pt/ZnO nanocomposite, producing CH 3 OH of 668 μmol g –1 , and the production rate of CH 3 OH over the 1.5% Pt/ZnO nanocomposite (74.11 μmol g –1 h –1 ) was increased 20 times in comparison with ZnO NPs (3.72 μmol g –1 h –1 ). The enhancement of CO 2 photoreduction efficiency over Pt/ZnO nanocomposites was attributed to the formation of the heterojunction at the Pt/ZnO interface, promoting a lower resistance to charge transfer and a larger electron transfer to the conduction band. Mesoporous Pt/ZnO nanocomposites offer enhanced accessibility and a larger surface area. Such an unparalleled mesostructure provides a new framework for the construction and design of photoactive materials with high-efficiency photocatalysts.

Plasmonic Solar Energy Harvesting by ZnO Nanostructures and Their Composite Interfaces: A Review on Fundamentals, Recent Advances, and Applications

“…It encourages a greater transfer of electrons to the conduction band and a reduction in charge transfer resistance. [ 379 ] C 1 (CO, CH 3 OH, and CH 4 ) is the primary result of the CO 2 hydrogenation reaction obtained via reverse water−gas shift reaction, CO 2 (g) + H 2 (g) → gCO(g) + H 2 O(g). Being an important precursor molecule, CO can be utilized to synthesize CH 3 OH molecules and long‐chain hydrocarbon production as well.…”

“…It encourages a greater transfer of electrons to the conduction band and a reduction in charge transfer resistance. [379] C 1 (CO, CH 3 OH, and CH 4 ) is the primary result of the CO 2 hydrogenation reaction obtained via reverse waterÀgas shift reaction, CO 2 (g) þ H 2 (g) ! gCO(g) þ H 2 O(g).…”

Photocatalytic Gold Recovery from Industrial Gold Plating Effluent by ZnO Nanoparticles: Optimum Condition and Possible Applications

“…Currently, zinc oxide (ZnO) has emerged as a promising alternative to TiO 2 driven by its cost-effectiveness, nontoxicity, high electron mobility, excellent electronic and optical properties, straightforward nanostructure modulation, and ease of reconfiguration. , Besides, despite sharing a comparable bandgap energy with TiO 2 , it exhibits a high efficiency to absorb a substantial portion of the solar spectrum . Based on literature, ZnO NPs have been applied in air purification, dye degradation, antibacterial materials, and hydrogen production. − Notably, several metal-doped ZnO NPs were applied for photocatalytic applications such as Au/ZnO, − Pt/ZnO, , Ag/ZnO, and Pd/ZnO . However, the utilization of ZnO or ZnO-based NPs for photocatalytic metal ion removal and recovery has been relatively scarce.…”

“… 26 Based on literature, ZnO NPs have been applied in air purification, dye degradation, antibacterial materials, and hydrogen production. 27 − 29 Notably, several metal-doped ZnO NPs were applied for photocatalytic applications such as Au/ZnO, 30 − 32 Pt/ZnO, 33 , 34 Ag/ZnO, 35 and Pd/ZnO. 36 However, the utilization of ZnO or ZnO-based NPs for photocatalytic metal ion removal and recovery has been relatively scarce.…”