The synergistic effects of Pt-OH and Pt⁰ enhanced the low-temperature catalytic performance of Pt/CNTs for preferential CO oxidation in a H₂ stream

Abstract

In the current era of pursuing low carbon, hydrogen energy emerged as a pivotal zero-carbon energy source, but faces a critical challenge in terms of its practical implementation. Trace CO contaminants (~1% CO) in industrial hydrogen streams derived from hydrocarbon reforming can irreversibly poison Pt electrodes of proton-exchange-membrane fuel cells. The preferential oxidation of CO in H₂-rich stream (PROX) is considered as an effective strategy to eliminate CO. In this work, we synthesized the catalyst of 0.3Pt/CNTs-CIW via a colloidal impregnation method, which achieves unprecedented performance in PROX, delivering 100% CO conversion with 50% CO₂ selectivity across an exceptionally broad operational temperature window from 20 to 200 °C with a minimal Pt content of 0.3 wt%. Various characterizations reveal that the high efficiency derives from the active structures with the synergies of Pt-OH and Pt⁰. The adsorption of CO is weakened by the construction of Pt-OH and couples with OH in the form of COOH^* which is then oxidized by OH^* derived from adsorbed O₂ and H₂ on Pt⁰ with a low activation energy, resulting in high efficiency of CO oxidation. Beyond CO-PROX, this bifunction activation paradigm offers transformative potential for diverse catalytic systems involving competitive adsorption and redox coupling, such as low-temperature oxidation of methane and volatile organic compounds abatement.

Keywords

CO oxidation / hydrogen / Pt/CNTs / hydroxyls / synergy

References

[1] Wei K,Ge J.Towards bridging thermo/electrocatalytic CO oxidation: from nanoparticles to single atoms.Chem Soc Rev2024;53:8903-48

[2] Park ED,Lee HC.Recent progress in selective CO removal in a H₂-rich stream.Catalysis Today2009;139:280-90

[3] Liu K,Zhang T.Recent advances in preferential oxidation of CO reaction over platinum group metal catalysts.ACS Catal2012;2:1165-78

[4] Zhang J,Niu Y.Advances in CO catalytic oxidation on typical noble metal catalysts: mechanism, performance and optimization.Chem Eng J2024;495:153523

[5] Jing P,Liu B.Recent advances in synergistic effect promoted catalysts for preferential oxidation of carbon monoxide.Catal Sci Technol2020;10:919-34

[6] Cao J,Wang J.Stearic acid induced hydrophobization of Pt/Al₂O₃ catalysts to boost the stability of preferential oxidation of CO in hydrogen.Ind Eng Chem Res2024;63:14622-30

[7] Qiao B,Yang X.Single-atom catalysis of CO oxidation using Pt1/FeOx.Nat Chem2011;3:634-41

[8] Song X,Ye Q,Guan Q.Innovative charge-tuning for highly dispersed Pt catalysts: achieving deep CO removal in industrial H₂ purification for fuel cells.ACS Appl Mater Interfaces2024;16:52529-38

[9] Shen J,Song L.Understanding the impact of hydroxyls on synthesizing the bimetallic alloy Pt₃Co on Al₂O₃ for CO-PROX.Fuel2025;379:133066

[10] Wang C,Lin H.Carbon nanotube-supported Pt-Co bimetallic catalysts for preferential oxidation of CO in a H₂-rich stream with CO₂ and H₂O vapor.J Power Sources2012;202:200-8

[11] Zhou X,Ma R,Guan Q.CuO nano-island anchored Pt catalyst for CO preferential oxidation in H₂-rich stream.Chem Eng J2024;495:153295

[12] Li Y,Du M.Unraveling distinct effects between CuOx and PtCu alloy sites in Pt-Cu bimetallic catalysts for CO oxidation at different temperatures.Nat Commun2024;15:5598 PMCID:PMC11222431

[13] Jardim E,Rico-francés S,Silvestre-albero J.Superior performance of multi-wall carbon nanotubes as support of Pt-based catalysts for the preferential CO oxidation: effect of ceria addition.Appl Catal B Environ2012;113-4:72-8

[14] Chen Y,Li L,Wang X.Local structure of Pt species dictates remarkable performance on Pt/Al₂O₃ for preferential oxidation of CO in H₂.Appl Catal B Environ2021;282:119588

[15] Lin J,Liu J.Design of a highly active Ir/Fe(OH)_x catalyst: versatile application of Pt-group metals for the preferential oxidation of carbon monoxide.Angew Chem Int Ed Engl2012;51:2920-4

[16] Cao J,Wang J.Stearic acid induced hydrophobization of Pt/Al₂O₃ catalysts to boost the stability of preferential oxidation of CO in hydrogen.Ind Eng Chem Res2024;63:14622-30

[17] Jia Z,Chen Y.Fully-exposed Pt-Fe cluster for efficient preferential oxidation of CO towards hydrogen purification.Nat Commun2022;13:6798 PMCID:PMC9649773

[18] Gashnikova D,Sauter E.Highly active oxidation catalysts through confining Pd clusters on CeO₂ nano-islands.Angew Chem Int Ed Engl2024;63:e202408511

[19] Wang S,Zong X,Dong X.CO oxidation with Pt catalysts supported on different supports: a comparison of their sulfur tolerance properties.Appl Catal A Gen2023;654:119083

[20] Naitabdi A,Rochet F.CO oxidation activity of Pt, Zn and ZnPt nanocatalysts: a comparative study by in situ near-ambient pressure X-ray photoelectron spectroscopy.Nanoscale2018;10:6566-80

[21] Hu X,Wang W.Structural features and catalytic performance in CO preferential oxidation of MWCNT-supported Pt-Fe catalysts.Int J Hydrogen Energy2016;41:14079-87

[22] Mu R,Xu H.Synergetic effect of surface and subsurface Ni species at Pt-Ni bimetallic catalysts for CO oxidation.J Am Chem Soc2011;133:1978-86

[23] Gerber IC.A theory/experience description of support effects in carbon-supported catalysts.Chem Rev2020;120:1250-349

[24] Tanaka K.-I, Shou M, Yuan Y. Low temperature PROX reaction of CO catalyzed by dual functional catalysis of the Pt supported on CNT, CNF, graphite, and amorphous-C with Ni-MgO, Fe, and Fe-Al₂O₃: oxidation of CO via HCOO Intermediate.J Phys Chem C2010;114:16917-23

[25] Sun X,Chen Y.Unravelling platinum nanoclusters as active sites to lower the catalyst loading for formaldehyde oxidation.Commun Chem2019;2:129

[26] Sun X,Zhou Y.FeO_x supported single-atom Pd bifunctional catalyst for water gas shift reaction.AIChE Journal2017;63:4022-31

[27] Chen L,Sun Y,Ye D.The graphitic carbon strengthened synergetic effect between Pt and FeNi in CO preferential oxidation in excess hydrogen at low temperature.Catal Sci Technol2016;6:98-106

[28] Xu H,Yao Y.Highly active Pt-Fe bicomponent catalysts for CO oxidation in the presence and absence of H₂.Energy Environ Sci2012;5:6313-20

[29] Guo X,Ning Y.Ferrous centers confined on core-shell nanostructures for low-temperature CO oxidation.J Am Chem Soc2012;134:12350-3

[30] Caglayan BS,Aksoylu AE.Preferential oxidation of CO over Pt-Sn/AC catalyst: adsorption, performance and DRIFTS studies.Appl Catal B Environ2011;106:540-9

[31] Şimşek E,Aksoylu AE.Preferential CO oxidation over activated carbon supported catalysts in H₂-rich gas streams containing CO₂ and H₂O.Appl Catal A Gen2007;316:169-74

[32] Yang H,Li B,Tanaka K.Doping effects of Ni-MgO on the structure and performance of carbon nanotube-supported Pt catalysts for preferential oxidation of CO in a H₂ stream.Appl Catal A Gen2011;402:168-75

[33] Chen L,Hoffman AS.Unlocking the catalytic potential of TiO₂-supported Pt single atoms for the reverse water-gas shift reaction by altering their chemical environment.JACS Au2021;1:977-86 PMCID:PMC8395703

[34] Zhao Z,Ma P.Atomically dispersed Pt/CeO₂ catalyst with superior CO selectivity in reverse water gas shift reaction.Appl Catal B Environ2021;291:120101

[35] Quinson J,Wannmacher T.Colloids for catalysts: a concept for the preparation of superior catalysts of industrial relevance.Angew Chem Int Ed Engl2018;57:12338-41 PMCID:PMC6175418

[36] Men Y,Wang Q.Highly dispersed Pt-based catalysts for selective CO₂ hydrogenation to methanol at atmospheric pressure.Chem Eng Sci2019;200:167-75

[37] Park JY,Renzas JR,Somorjai GA.The role of organic capping layers of platinum nanoparticles in catalytic activity of CO oxidation.Catal Lett2009;129:1-6

[38] Zhang J,Wang R.Switching of CO₂ hydrogenation selectivity via chlorine poisoning over Ru/TiO₂ catalyst.Nano Res2023;16:4786-92

[39] Li Y,Su Y,Qiao B.Maximized Ir atom utilization via downsizing active sites to single-atom scale for highly stable dry reforming of methane.Chem Synth2024;4:61

[40] Quinson J,Neumann S.Investigating particle size effects in catalysis by applying a size-controlled and surfactant-free synthesis of colloidal nanoparticles in alkaline ethylene glycol: case study of the oxygen reduction reaction on Pt.ACS Catal2018;8:6627-35

[41] Chen Y,Li L.Identification of active sites on high-performance Pt/Al₂O₃ catalyst for cryogenic CO oxidation.ACS Catal2020;10:8815-24

[42] DeRita L,Dai S.Structural evolution of atomically dispersed Pt catalysts dictates reactivity.Nat Mater2019;18:746-51

[43] Sun X,Wang Y.Catalytically active Ir0 species supported on Al₂O₃ for complete oxidation of formaldehyde at ambient temperature.Appl Catal B Environ2020;268:118741

[44] Chen W,Fu W.Molecular-level insights into the notorious CO poisoning of platinum catalyst.Angew Chem Int Ed Engl2022;61:e202200190

[45] Chen L,Nguyen MT.Dynamic evolution of palladium single atoms on anatase titania support determines the reverse water-gas shift activity.J Am Chem Soc2023;145:10847-60

[46] Therrien AJ,Marcinkowski MD.An atomic-scale view of single-site Pt catalysis for low-temperature CO oxidation.Nat Catal2018;1:192-8

[47] Lin J,Li L.Remarkable effects of hydroxyl species on low-temperature CO (preferential) oxidation over Ir/Fe(OH)_x catalyst.J Catal2014;319:142-9

[48] Sun X,Cui J,Lin J.Noble-metal-based catalysts on a scale from nanoparticles to subnanoclusters and single atoms for formaldehyde oxidation at room temperature: a review.ACS Appl Nano Mater2024;7:3546-63

[49] Chen Y.Design of efficient noble metal single-atom and cluster catalysts toward low-temperature preferential oxidation of CO in H₂.Int J Hydrogen Energy2023;48:24788-808

[50] Wang HF,Guo YL,Lu GZ.Structural origin: water deactivates metal oxides to CO oxidation and promotes low-temperature CO oxidation with metals.Angew Chem Int Ed Engl2012;51:6657-61

[51] Zhang C,Zhai Y.Alkali-metal-promoted Pt/TiO₂ opens a more efficient pathway to formaldehyde oxidation at ambient temperatures.Angew Chem Int Ed Engl2012;51:9628-32

[52] Huang Z,Xu Y.Water promoting effect in CO oxidation over N-doped Co₃O₄/Pt nanocatalysts by tailoring metal-support interfaces.Chem Catalysis2023;3:100692

[53] Xie Y,Zhang H.Improvement role of CNTs on catalytic performance in the CeO₂/xCNTs-CuO catalysts.Int J Hydrogen Energy2016;41:21979-89