{"id":{"repo_id":"houston","oai_identifier":"oai:uh-ir.tdl.org:10657/20920"},"canonical_url":"https://search.dev.ndltd.org/etd/houston/oai:uh-ir.tdl.org:10657/20920","repository":{"repo_id":"houston","name":"University of Houston","base_url":"https://uh-ir.tdl.org/server/oai/request"},"display":{"title":"Non-Thermal Contribution to Ruthenium Photothermal Catalyst in Carbon Dioxide Methanation","abstract":"Global economic growth has been accompanied by an increase in energy consumption and the release of CO2 into the atmosphere. Photothermal catalysis offers a promising strategy for sustainable chemical transformations by combining thermal and photonic energy to accelerate reactions under mild conditions to convert greenhouses into energy sources. However, quantifying non-thermal contributions, particularly those arising from hot electrons, remains a major challenge due to limitations in temperature measurement and mechanistic ambiguity. This dissertation addresses these challenges through the development of a non-contact near-infrared (NIR) optical thermometer capable of accurately measuring catalyst surface temperature independent of emissivity. By fitting the continuous NIR emission spectrum (950–1600 nm), this technique achieves ±1 °C accuracy above 200 °C, enabling reliable distinction between thermal and non-thermal effects. Using Ru–SiO2 as a model system for CO₂ methanation, we demonstrate over 100-fold enhancement in CH4 production in blue light compared to green light. The reaction rate scales nearly linearly with light intensity and exhibits a sharp spectral cutoff near 500 nm, disappearing at longer wavelengths. This wavelength dependence suggests a non-thermal mechanism beyond simple heating. By integrating precise temperature monitoring, studying dependence on photon energy and intensities with and without external heating, this work establishes a mechanistic framework for validating non-thermal contributions in photothermal catalysis. The approach is generalizable to other catalytic systems and offers design principles for next-generation catalysts that leverage light–matter interactions to enhance selectivity, reduce activation barriers, and enable sustainable chemical transformations.","abstract_html":"Global economic growth has been accompanied by an increase in energy consumption and the release of CO2 into the atmosphere. Photothermal catalysis offers a promising strategy for sustainable chemical transformations by combining thermal and photonic energy to accelerate reactions under mild conditions to convert greenhouses into energy sources. However, quantifying non-thermal contributions, particularly those arising from hot electrons, remains a major challenge due to limitations in temperature measurement and mechanistic ambiguity. This dissertation addresses these challenges through the development of a non-contact near-infrared (NIR) optical thermometer capable of accurately measuring catalyst surface temperature independent of emissivity. By fitting the continuous NIR emission spectrum (950–1600 nm), this technique achieves ±1 °C accuracy above 200 °C, enabling reliable distinction between thermal and non-thermal effects. Using Ru–SiO2 as a model system for CO₂ methanation, we demonstrate over 100-fold enhancement in CH4 production in blue light compared to green light. The reaction rate scales nearly linearly with light intensity and exhibits a sharp spectral cutoff near 500 nm, disappearing at longer wavelengths. This wavelength dependence suggests a non-thermal mechanism beyond simple heating. By integrating precise temperature monitoring, studying dependence on photon energy and intensities with and without external heating, this work establishes a mechanistic framework for validating non-thermal contributions in photothermal catalysis. The approach is generalizable to other catalytic systems and offers design principles for next-generation catalysts that leverage light–matter interactions to enhance selectivity, reduce activation barriers, and enable sustainable chemical transformations.","abstract_has_math":false,"creators":["Chirom, Meiraba Meitei 1997-"],"institution":"University of Houston","degree_name":"Doctor of Philosophy","degree_level":null,"degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":[],"advisors":["Baldelli, Steven","Bao, Jiming"],"committee_chairs":[],"committee_members":["Brgoch, Jakoah","Jacobson, Allan J.","Dreyer, Daniel"],"year":2025,"date_issued":"2025-12","date_published":"2025-12","updated_at":"2026-07-24T02:31:59Z","subjects":["Plasmonics","CO2 methanation","Non contact thermometry","Photothermal catalysis","Non-thermal contribution","Reaction mechanism","Ruthenium catalyst"],"languages":["English"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10657/20920","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Baldelli, Steven","Bao, Jiming"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Brgoch, Jakoah","Jacobson, Allan J.","Dreyer, Daniel"]},{"key":"dc:creator","label":"Author","values":["Chirom, Meiraba Meitei 1997-"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-02-10T18:17:21Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-12"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Houston"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Plasmonics","CO2 methanation","Non contact thermometry","Photothermal catalysis","Non-thermal contribution","Reaction mechanism","Ruthenium catalyst"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["English"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10657/20920"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Global economic growth has been accompanied by an increase in energy consumption and the release of CO2 into the atmosphere. Photothermal catalysis offers a promising strategy for sustainable chemical transformations by combining thermal and photonic energy to accelerate reactions under mild conditions to convert greenhouses into energy sources. However, quantifying non-thermal contributions, particularly those arising from hot electrons, remains a major challenge due to limitations in temperature measurement and mechanistic ambiguity. This dissertation addresses these challenges through the development of a non-contact near-infrared (NIR) optical thermometer capable of accurately measuring catalyst surface temperature independent of emissivity. By fitting the continuous NIR emission spectrum (950–1600 nm), this technique achieves ±1 °C accuracy above 200 °C, enabling reliable distinction between thermal and non-thermal effects. Using Ru–SiO2 as a model system for CO₂ methanation, we demonstrate over 100-fold enhancement in CH4 production in blue light compared to green light. The reaction rate scales nearly linearly with light intensity and exhibits a sharp spectral cutoff near 500 nm, disappearing at longer wavelengths. This wavelength dependence suggests a non-thermal mechanism beyond simple heating. By integrating precise temperature monitoring, studying dependence on photon energy and intensities with and without external heating, this work establishes a mechanistic framework for validating non-thermal contributions in photothermal catalysis. The approach is generalizable to other catalytic systems and offers design principles for next-generation catalysts that leverage light–matter interactions to enhance selectivity, reduce activation barriers, and enable sustainable chemical transformations."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Non-Thermal Contribution to Ruthenium Photothermal Catalyst in Carbon Dioxide Methanation"]}]}],"canonical_facts":{"dc:contributor.advisor":["Baldelli, Steven","Bao, Jiming"],"dc:contributor.committeemember":["Brgoch, Jakoah","Jacobson, Allan J.","Dreyer, Daniel"],"dc:creator":["Chirom, Meiraba Meitei 1997-"],"dc:date.accessioned":["2026-02-10T18:17:21Z"],"dc:date.issued":["2025-12"],"dc:description.abstract":["Global economic growth has been accompanied by an increase in energy consumption and the release of CO2 into the atmosphere. Photothermal catalysis offers a promising strategy for sustainable chemical transformations by combining thermal and photonic energy to accelerate reactions under mild conditions to convert greenhouses into energy sources. However, quantifying non-thermal contributions, particularly those arising from hot electrons, remains a major challenge due to limitations in temperature measurement and mechanistic ambiguity. This dissertation addresses these challenges through the development of a non-contact near-infrared (NIR) optical thermometer capable of accurately measuring catalyst surface temperature independent of emissivity. By fitting the continuous NIR emission spectrum (950–1600 nm), this technique achieves ±1 °C accuracy above 200 °C, enabling reliable distinction between thermal and non-thermal effects. Using Ru–SiO2 as a model system for CO₂ methanation, we demonstrate over 100-fold enhancement in CH4 production in blue light compared to green light. The reaction rate scales nearly linearly with light intensity and exhibits a sharp spectral cutoff near 500 nm, disappearing at longer wavelengths. This wavelength dependence suggests a non-thermal mechanism beyond simple heating. By integrating precise temperature monitoring, studying dependence on photon energy and intensities with and without external heating, this work establishes a mechanistic framework for validating non-thermal contributions in photothermal catalysis. The approach is generalizable to other catalytic systems and offers design principles for next-generation catalysts that leverage light–matter interactions to enhance selectivity, reduce activation barriers, and enable sustainable chemical transformations."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/10657/20920"],"dc:language.iso":["English"],"dc:subject":["Plasmonics","CO2 methanation","Non contact thermometry","Photothermal catalysis","Non-thermal contribution","Reaction mechanism","Ruthenium catalyst"],"dc:title":["Non-Thermal Contribution to Ruthenium Photothermal Catalyst in Carbon Dioxide Methanation"],"dc:type":["Thesis"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["University of Houston"]},"updated_at":"2026-07-24T02:31:59Z"}