Tuning of Pt–Co nanoparticle motifs for enhancing the HOR performance in alkaline media

Weber, Daniel; Dosche, Carsten; Oezaslan, Mehtap

doi:10.1039/d1ta02067f

Cited by 28 publications

(16 citation statements)

References 70 publications

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“…According to well-established volcano plots of exchange current and calculated hydrogen binding energy (HBE, ΔG 0 H* ), good HOR catalysts like Pt show the optimal ΔG 0 H* value close to zero, [4,9] but stronger adsorption of H* on Pt sites takes place as pH increases from 1 to 14. [10,11] This issue can be solved by alloying Pt with secondary metal, such as Ru, [12][13][14][15] Pd, [3] Ni or its oxides, [16][17][18] Co, [19,20] and Cu, [21] to optimize the electronic density around Pt sites or oxophilic character. In this view, Markovic et al reported that the addition of Ru element into Pt catalyst rose the mass activity by about sixfold when compared to catalysts without modification.…”

Section: Introductionmentioning

confidence: 99%

Single‐Atom Molybdenum Engineered Platinum Nanocatalyst for Boosted Alkaline Hydrogen Oxidation

Yan

et al. 2022

Advanced Energy Materials

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Engineering the surface electrochemistry at the atomic level can precisely and effectively manipulate the reactivity and durability of catalysts. Herein, a novel single‐atom fine‐tailoring strategy based on a highly hydrophilic Mo‐bifunctional promoter is proposed to greatly boost the hydrogen oxidation reaction (HOR) on Pt catalysts. The single‐atom Mo‐modified nanometer Pt anchored on porous N‐doped carbon (Mo‐Pt/NC) is developed via a pyrolysis–adsorption–reduction process. The designed Mo‐Pt/NC exhibits a remarkable mass‐specific kinetic current reaching 1584 mA mg−1Pt in 0.1 m KOH, which is nearly 11‐fold and fourfold higher than the activities of commercial Pt/C and Pt/NC counterparts respectively, and such extraordinary HOR behavior even exceeds those of documented Pt‐related catalysts. Electrochemical and spectroscopic studies indicate that hydrophilic Mo single‐atom sites can not only regulate the electronic microenvironment of Pt sites for attenuated H* adsorption, but they also serve as energetic H2O*‐adsorption promoters to jointly facilitate the HOR kinetics. Moreover, the anti‐CO poisoning capability of Mo‐Pt/NC is markedly enhanced by this Mo‐modified electronic effect. This work gives a significant guideline for the design of high‐performance HOR catalysts and other advanced catalysts.

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Section: Introductionmentioning

confidence: 99%

Single‐Atom Molybdenum Engineered Platinum Nanocatalyst for Boosted Alkaline Hydrogen Oxidation

Yan

et al. 2022

Advanced Energy Materials

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“…We want to emphasize that the dealloying protocol has a huge impact on the resulting ECSA values for these precursor catalyst materials. 69 3.2. Chemical State of Both Metals in Dealloyed Pt x Co 1−x Core−Shell Nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

Highly Durable Pt-Based Core–Shell Catalysts with Metallic and Oxidized Co Species for Boosting the Oxygen Reduction Reaction

Weber

Dosche

et al. 2022

ACS Catal.

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Over the last 15 years, core–shell nanoparticles with a Pt-enriched shell have emerged as efficient electrocatalysts for the oxygen reduction reaction (ORR). However, to what extent the chemical state of the cobalt species inside the particle core has influence on the ORR performance and particularly on the long-term durability has not yet fully understood to date. In this study, we investigate the chemical state of the internal cobalt atoms and their stability within the Pt x Co1–x core–shell catalysts during the ORR as well as after applying different accelerated stress test (AST) protocols. Remarkably, at the begin-of-life, the activated Pt x Co1–x core–shell catalysts exhibit over 3.7–5.3 increase in Pt mass-based activity and over 5.8–10.6 increase in Pt surface area-specific activity at 0.95 VRHE compared to Pt/C. The superior ORR activity originates from the chemical composition of the particle core, where cobalt not only exists in the metallic state but also as 40–60% of Co oxide species detected by X-ray photoelectron spectroscopy. The Co oxide species are very likely relics of the precursor catalyst from the activation process via electrochemical dealloying. Moreover, the Pt x Co1–x core–shell catalysts show improved durability and high cobalt retention against electrochemical dissolution during the AST protocols (e.g., >70% of Co after 2000 cycles between 0.5 and 1.5 VRHE). Although the potential cycle-dependent changes in the electrochemically active Pt surface area and particle size are negligible or moderate, the ORR activities of Pt x Co1–x core–shell catalysts decrease but still surpass that of Pt/C by a factor of 2–3. The observed loss of ORR performance for Pt x Co1–x core–shell catalysts is very likely related to Ostwald ripening as the main degradation process, which leads to increasing thickness of the Pt-enriched particle shell. Remarkably, the stability of the internal Co oxide species is barely affected under the aggressive AST conditions. Thus, we suggest that the Co oxide species might have a positive effect and could even be a yet undiscovered alternative to metallic cobalt to boost the ORR activity and the long-term durability of Pt x Co1–x core–shell catalysts beyond their expected useful life.

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“…Hydrogen oxidation reaction (HOR) is the key to meet the requirements of renewable and clean energy conversion and energy storage in the hydrogen economy soon. [ 119 ] For domestic fuel cells, the fuel gas rich in H 2 is obtained by reforming. Trace CO in the reforming product poisons the HOR on platinum and blocks the active site.…”

Section: Electrocatalytic Applications Of Pt–co Catalystsmentioning

confidence: 99%

“…Lastly, it was also found that the particle size did not affect the effect of polycrystalline and nanosized Pt on the HOR activity in the alkaline medium. [ 119 ]…”

Section: Electrocatalytic Applications Of Pt–co Catalystsmentioning

confidence: 99%

Pt–Co Electrocatalysts: Syntheses, Morphologies, and Applications

Chen

Liu

et al. 2022

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Pt–Co electrocatalysts have attracted significant attention because of their excellent performance in many electrochemical reactions. This review focuses on Pt–Co electrocatalysts designed and prepared for electrocatalytic applications. First, the various synthetic methods and synthesis mechanisms are systematically summarized; typical examples and core synthesis parameters are discussed for regulating the morphology and structure. Then, starting with the design and structure–activity relationship of catalysts, the research progress of the morphologies and structures of Pt–Co electrocatalysts obtained based on various strategies, the structure–activity relationship between them, and their properties are summarized. In addition, the important electrocatalytic applications and mechanisms of Pt–Co catalysts, including electrocatalytic oxidation/reduction and bifunctional catalytic reactions, are described and summarized, and their high catalytic activities are discussed on the basis of their mechanism and active sites. Moreover, the advanced electrochemical in situ characterization techniques are summarized, and the challenges and direction concerning the development of high‐performance Pt–Co catalysts in electrocatalysis are discussed.

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Tuning of Pt–Co nanoparticle motifs for enhancing the HOR performance in alkaline media

Abstract: For a future sustainable hydrogen economy, electrocatalysis of hydrogen oxidation/evolution reactions (HOR/HER) needs to be better understood. In order to describe the strong alteration of HOR/HER rates on platinum group...

Cited by 28 publications

References 70 publications

Single‐Atom Molybdenum Engineered Platinum Nanocatalyst for Boosted Alkaline Hydrogen Oxidation

Single‐Atom Molybdenum Engineered Platinum Nanocatalyst for Boosted Alkaline Hydrogen Oxidation

Highly Durable Pt-Based Core–Shell Catalysts with Metallic and Oxidized Co Species for Boosting the Oxygen Reduction Reaction

Pt–Co Electrocatalysts: Syntheses, Morphologies, and Applications

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