Photothermal Catalyst Engineering: Hydrogenation of Gaseous CO₂ with High Activity and Tailored Selectivity

Abstract

This study has designed and implemented a library of hetero‐nanostructured catalysts, denoted as Pd@Nb2O5, comprised of size‐controlled Pd nanocrystals interfaced with Nb2O5 nanorods. This study also demonstrates that the catalytic activity and selectivity of CO2 reduction to CO and CH4 products can be systematically tailored by varying the size of the Pd nanocrystals supported on the Nb2O5 nanorods. Using large Pd nanocrystals, this study achieves CO and CH4 production rates as high as 0.75 and 0.11 mol h−1 gPd −1, respectively. By contrast, using small Pd nanocrystals, a CO production rate surpassing 18.8 mol h−1 gPd −1 is observed with 99.5% CO selectivity. These performance metrics establish a new milestone in the champion league of catalytic nanomaterials that can enable solar‐powered gas‐phase heterogeneous CO2 reduction. The remarkable control over the catalytic performance of Pd@Nb2O5 is demonstrated to stem from a combination of photothermal, electronic and size effects, which is rationally tunable through nanochemistry.

Polymorph selection towards photocatalytic gaseous CO2 hydrogenation

“…Conversely, owing to the endothermic nature of the RWGS reaction, the CO rate is dramatically enhanced with increasing temperature and reaches about 2.4 mmol g cat −1 h −1 at 300 °C. Such a CO formation rate is comparable to some of the most active noble metal decorated catalysts 13,42 and ~ 3.2 times higher than that of the reference c-In 2 O 3-x (OH) y . Unlike CH 3 OH performance, which can be enhanced by the light irradiation, CO performance was only enhanced by ∼ 0.5 % under light irradiation (activation energy of ∼ 84.8 kJ mol −1 for both light and dark), which results in an enhanced solar CH 3 OH selectivity (Supplementary Fig.…”

Sunlight-assisted hydrogenation of CO 2 into ethanol and C2+ hydrocarbons by sodium-promoted Co@C nanocomposites

“…In previous works, it has been reported that CO2 hydrogenation can be enhanced under solar light irradiation. 12,32 Herein, we have also observed that the initial reaction rate of the CO2 hydrogenation on Na-Co@C under thermal conditions was lower than for the analogous process performed under photothermal conditions (see Figure S6). The Na-Co@C nanomaterials show an intense light absorption profile throughout the entire UV-vis spectrum (see Figure S7).…”

Nanostructured Ternary Metal Tungstate-Based Photocatalysts for Environmental Purification and Solar Water Splitting: A Review

“…In general, a complete semiconductor photocatalytic cycle involves light-harvesting, photogenerated charge carrier excitation, charge separation and transfer, and surface redox reactions [ 4 – 6 ] that allow for the formation of reactive oxygen species (ROSs), such as free electrons (e − ), hydrogen peroxide (H 2 O 2 ), hydroxyl (·OH), and superoxide radicals (·O 2 − ) [ 7 , 8 ]. The aforementioned ROSs play crucial roles in various important applications, including photocatalysis [ 9 – 12 ], photoelectrocatalysis [ 13 – 17 ], plasma photocatalysis [ 18 , 19 ], and photothermocatalysis [ 20 – 22 ]. Until now, TiO 2 has been among the most extensively studied semiconductor photocatalysts because of its strong oxidative ability, chemical stability, long durability, and nontoxicity [ 23 – 25 ].…”