A new hybrid catalyst composed of mesostructured silica SBA-15 functionalized with TiO2 and further loaded
with RuO2 was developed to efficiently promote thermo-photocatalytic CO2 hydrogenation into methane at low
temperatures. The catalytic activity was assessed with respect to TiO2:RuO2 loading, catalyst dosage, illumination
source (polychromatic sunlight and monochromatic LEDs) and power, [H2]:[CO2] molar ratio, temperature,
and catalyst reusability. The best methanation yields were attained for the RuO2(6.4%):TiO2(16.9%)/SBA-15
nanocomposite at 150 ºC, under simulated sunlight (0.21 W) and stoichiometric [H2]:[CO2] molar ratio,
reaching: a specific CH4 production rate of 13.6 mmol g-c1a t h-1; 99.8 % selectivity; 96.8 % CO2 conversion (110-
min; 40 mL); and apparent photonic efficiency/quantum yield of 39.5 %/42.1 %. Considering only the active
RuO2:TiO2 photocatalyst mass (23.3 %), the CH4 production rate increased to 58.6 mmol g-a1c tive_cat h-1. Besides,
this highly-active photocatalyst featured excellent UV-Vis-IR light absorbance, high surface area, and stability for
reuse when moist gas was removed between cycles.
This work was financially supported by: (i) LA/P/0045/2020
(ALiCE), UIDB/50020/2020 and UIDP/50020/2020 (LSRE-LCM), funded
by national funds through Fundação para a Ciência e a Tecnologia
(FCT), and Ministério da Ciência, Tecnologia e Ensino Superior (MCTES),
Portugal, under Programa de Investimento e Despesas de Desenvolvimento
da Administração Central (PIDDAC); (ii) project HyGreen&LowEmissions
(NORTE-01-0145-FEDER-000077), supported by Norte Portugal
Regional Operational Programme (NORTE 2020), under the PORTUGAL
2020 Partnership Agreement, through the European Regional Development
Fund (ERDF); and (iii) project CO2-to-CH4 (2022.01176. PTDC),
supported by national funds through the FCT/MCTES (PIDDAC). Larissa
O. Paulista acknowledges the Ph.D. fellowship supported by FCT
(reference SFRH/BD/137639/2018 and COVID/BD/152922/2022).
Maja B. Đolíc acknowledges the Ministry of Education, Science and
Technological Development of the Republic of Serbia (Contract No.
451–03-9/2022–14/200135). Tˆania F.C.V. Silva acknowledges the FCT
Individual Call to Scientific Employment Stimulus 2017 (CEECIND/
01386/2017).
