Formation of NiCo Alloy Nanoparticles on Co Doped Al₂O₃ Leads to High Fuel Production Rate, Large Light‐to‐Fuel Efficiency, and Excellent Durability for Photothermocatalytic CO₂ Reduction

Abstract

Unique nanocomposites of NiCo alloy nanoparticles with Ni/Co molar ratios of 1.86, 1.60, and 0.38 supported on Co‐doped Al2O3 nanosheets are prepared by a facile approach. Very high fuel production rates of CO (rCO) and H2 (rH2) (70.53 and 63.46 mmol min−1 g−1) and light‐to‐fuel efficiency (η, 29.7%) are achieved via photothermocatalytic CO2 reduction by methane (CRM) on Ni1.60Co/Co‐Al2O3 simply utilizing focused UV‐visible‐infrared (UV‐vis‐IR) illumination. Ni1.60Co/Co‐Al2O3 also demonstrates high rCO and rH2 values (50.99 and 39.72 mmol min−1 g−1) as well as high η value (26.3%) under λ > 560 nm focused vis‐IR illumination. The high photothermocatalytic activity is derived from the light‐driven thermocatalytic CRM. A novel photoactivation is found to substantially promote the light‐driven thermocatalytic CRM due to the apparent activation energy being considerably reduced upon illumination. It is found that the Ni/Co molar ratio in the NiCo/Co‐Al2O3 samples has an important effect on the photothermocatalytic durability. The samples of Ni1.60Co/Co‐Al2O3 and Ni1.86Co/Co‐Al2O3 with a higher Ni/Co molar ratio demonstrate excellent photothermocatalytic durability, while the Ni0.38Co/Co‐Al2O3 with a lower Ni/Co molar ratio has less durability. This is attributed to carbon deposition rate being significantly reduced on Ni1.60Co/Co‐Al2O3 and Ni1.86Co/Co‐Al2O3 as compared to its single metal counterparts.

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

“…The optical absorption of CuTi alloy induces the excitation of 3d orbital, computed by alternating the electron number in the up-and down-spin configuration. [12,29] The reaction energy difference ΔE of CO oxidation on Cu 2 O 2 /TiO 2 slab in the ground state or excited state is calculated as follows.…”

Photothermocatalytic CO2 Reduction on Magnesium Oxide‐Cluster‐Modified Ni Nanoparticles with High Fuel Production Rate, Large Light‐to‐Fuel Efficiency and Excellent Durability

“…The strategies involve photocatalytic CO 2 reduction by H 2 O [ 1–25 ] and organic compounds (e.g., triethanolamine, CH 4 ) as electron donors, [ 26–34 ] light‐driven thermochemical splitting of CO 2 , [ 35–40 ] photothermocatalytic CO 2 reduction by H 2 O, [ 41–45 ] H 2 , [ 46–50 ] and CH 4 (photothermocatalytic CO 2 reduction by CH 4 (CRM): CO 2 + CH 4 = 2CO + 2H 2 , Δ H 298 = 247 kJ mol −1 ). [ 51–59 ] For the potential application of the strategies, high fuel production rate ( r fuel ), large light‐to‐fuel efficiency ( η ), and excellent durability are prerequisite. The photocatalytic strategies using semiconductor photocatalysts has the advantage of operating at ambient temperature, but low r fuel and η are two major obstacles to be overcome due to the recombination of the majority of the photogenerated chargers and the difficult in the utilization of infrared energy in solar light.…”

“…[ 1–34 ] Photothermocatalytic CRM is very promising as both r fuel and η could be simultaneously achieved. [ 53–57 ] The main catalysts for photothermocatalytic CRM reported are supported group VIII metal nanoparticles (e.g., Pt, Rh, Ru, Ni, Co, etc.) due to their good thermocatalytic activity and strong surface plasmonic absorption.…”

“…due to their good thermocatalytic activity and strong surface plasmonic absorption. [ 51–60 ] Among the catalysts, supported nonprecious group VIII metal nanoparticles (e.g., Ni, Co) are very attractive due to their good photothermocatalytic activity, low cost, and earth abundance. For photothermocatalytic CRM on supported nonprecious group VIII metal nanoparticles, the great challenge to be addressed is severe carbon deposition due to the two side reactions of carbon deposition such as CO disproportionation (2CO = C + CO 2 , Δ H 298 = −171 kJ mol −1 ) and CH 4 complete dissociation (CH 4 = C + 2H 2 , Δ H 298 = 75 kJ mol −1 ) accompanying with CRM.…”

Thermal CO Oxidation and Photocatalytic CO2 Reduction over Bare and M-Al2O3 (M = Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) Cotton-Like Nanosheets

“…Aluminum oxide (Al 2 O 3 ) has extensively been used as a heterogeneous catalyst in diverse catalytic reactions of CO oxidation [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], CO 2 reduction [20][21][22][23], CO 2 methanation/hydrogenation [20,[24][25][26][27], and preferential oxidation of CO [28,29]. The efforts to increase the catalytic activity of the metal oxide have been devoted to the modification of the metal surface by loading of transition metals in groups of 9 (Co, Rh, and Ir), 10 (Ni, Pd, and Cu), and 11 (Cu, Ag, and Au).…”