Formic acid oxidation on AuPd core-shell electrocatalysts: Effect of surface electronic structure

Hernández, Adrián Romero; Arce-Estrada, E.M.; Ezeta-Mejía, A.; Manríquez, Ma.

doi:10.1016/j.electacta.2019.134977

Cited by 21 publications

(12 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Promoting Pd cubes with Sn appears to be very effective for boosting the catalytic activity, since SnO 2 @Pd NCs resulted in a j 0 value of 0.96 mA cm –2 , compared to Pd NCs with 0.44 mA cm –2 . The order of magnitude is in a similar range to values for Pd reported in the literature. − Thus, this result confirms the improved catalytic activity of SnO 2 @Pd NCs, mainly because of its enhanced electrokinetics.…”

Section: Resultssupporting

confidence: 89%

See 1 more Smart Citation

Enhanced Formic Acid Oxidation over SnO₂-decorated Pd Nanocubes

et al. 2020

View full text Add to dashboard Cite

The formic acid oxidation reaction (FAOR) is one of the key reactions that can be used at the anode of low-temperature liquid fuel cells. To allow the knowledge-driven development of improved catalysts, it is necessary to deeply understand the fundamental aspects of the FAOR, which can be ideally achieved by investigating highly active model catalysts. Here, we studied SnO 2 -decorated Pd nanocubes (NCs) exhibiting excellent electrocatalytic performance for formic acid oxidation in acidic medium with a SnO 2 promotion that boosts the catalytic activity by a factor of 5.8, compared to pure Pd NCs, exhibiting values of 2.46 A mg –1 Pd for SnO 2 @Pd NCs versus 0.42 A mg –1 Pd for the Pd NCs and a 100 mV lower peak potential. By using ex situ, quasi in situ, and operando spectroscopic and microscopic methods (namely, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption fine-structure spectroscopy), we identified that the initially well-defined SnO 2 -decorated Pd nanocubes maintain their structure and composition throughout FAOR. In situ Fourier-transformed infrared spectroscopy revealed a weaker CO adsorption site in the case of the SnO 2 -decorated Pd NCs, compared to the monometallic Pd NCs, enabling a bifunctional reaction mechanism. Therein, SnO 2 provides oxygen species to the Pd surface at low overpotentials, promoting the oxidation of the poisoning CO intermediate and, thus, improving the catalytic performance of Pd. Our SnO x -decorated Pd nanocubes allowed deeper insight into the mechanism of FAOR and hold promise for possible applications in direct formic acid fuel cells.

show abstract

Section: Resultssupporting

confidence: 89%

“…The order of magnitude is in a similar range to values for Pd reported in the literature. 65 − 67 Thus, this result confirms the improved catalytic activity of SnO 2 @Pd NCs, mainly because of its enhanced electrokinetics.…”

Section: Resultssupporting

confidence: 74%

Enhanced Formic Acid Oxidation over SnO₂-decorated Pd Nanocubes

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Alloying Pd with other elements such as Cu, Ni, Ru, Ag, or Au can further optimize the electronic structure of Pd for enhanced activity and stability [15][16][17][18][19][20]. Among various metals, Au is particularly attractive for the exploration of Pd-based binary systems because it contributes to the stabilization of Pd by inhibiting its dissolution under acidic high oxidation conditions, while pure Au itself is inert to FAOR [21,22]. Experimentally, Pd-Au bimetallic catalysts indeed demonstrate improved performance, which are attributed to the possible fundamental issues including geometric effect, electronic effect, faceting, or strain effect [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Highly coordinated Pd overlayers on nanoporous gold for efficient formic acid electro-oxidation

et al. 2021

View full text Add to dashboard Cite

Design and fabrication of highly efficient and stable electrocatalysts remain key challenges in green energy technologies such as low-temperature direct liquid fuel cells. Based on in-depth theoretical calculations, here we demonstrate that surface Pd atoms with high coordination numbers (HCNs) can effectively modulate their adsorption energies for CO and OH, and thus achieve very high performance for formic acid electro-oxidation reaction (FAOR). Based on epitaxial coating Pd atomic layers onto nanoporous gold (NPG) thin membranes and a slight further decoration of Au clusters on top, the resulted core-shell structured NPG-Pd-Au electrocatalyst can demonstrate Pd intrinsic and mass activities of 8.62 mA•cm −2 and 27.25 A•mg −1 respectively at the peak potential around 0.33 V versus saturated calomel electrode toward FAOR, which are far better than those of commercial Pd/C catalysts (1.09 mA•cm −2 and 0.32 A•mg −1 ) tested under the same conditions. Moreover, the membrane electrode assemblies based on these low precious metal loading electrodes can achieve an anode Pd power efficiency over 10 W•mg −1 in a direct formic acid fuel cell, which is two orders of magnitude higher than that of the commercial Pd/C. These results provide new inspirations for the development of revolutionary electrodes for energy technologies in a rational manner.

show abstract

“…To efficiently catalyze this reaction, catalysts are required and the most efficient materials relied on the noble metal of Pt and Pd based catalysts 4,5 . It was recognized that Pt catalysts exhibited poor catalytic performance arising from CO poisoning accumulated by the dehydration step [6][7][8] . Compared with Pt catalysts, the electro-oxidation of formic acid on Pd catalysts is mainly performed through the direct pathway, thus it has a very low CO poisoning effect 9 .…”

Section: Introductionmentioning

confidence: 99%

Formic Acid Electro-oxidation Catalyzed by PdNi/Graphene Aerogel

Bao¹,

Feng²

2020

Acta Physico Chimica Sinica

View full text Add to dashboard Cite

Direct formic acid fuel cells involve two significant half-reactions, namely formic acid electro-oxidation and oxygen reduction reaction, and the more sluggish and complex process for anode formic acid oxide also determine the whole fuel cells energy conversion efficiency. The most efficient catalysts rely on the noble metal of Pt and Pd based catalysts and compared with Pt catalysts, Pd catalyst is more appealing because of the low CO poisoning effect during the electro-oxidation of formic acid that mainly follows the direct pathway. The Pd alloy effect and support effect should be considered for the catalyst fabrication since the resulted structure and electronic modification could largely increase the catalytic performance. Graphene emerges out as novel support while the easy agglomeration and destruction of pure graphene do not guarantee promising merits. In this work, we demonstrated the formic acid oxidation ability boosting by facile coupling PdNi alloy and 3D graphene aerogel (PdNi/GA) via a freezingdrying/thermal annealing reduction approach. The PdNi alloy crystal structure was well confirmed by the X-ray diffractions technique and the alloy nanoparticles were successfully anchored on the 3D graphene aerogel surface. The electrochemical performance was evaluated for formic acid oxidation in the acid electrolyte. The PdNi/GA catalyst displayed a larger peak current density of 136 mA•cm −2 , which was 2 and 3.45 times greater than Pd/GA (68 mA•cm −2 ) and Pd/C (39.4 mA•cm −2 ), respectively. The anti-CO poisoning ability was measured by CO stripping technique, and a low onset potential of 0.49 V was found on PdNi/GA catalyst, about 120 mV less than that of Pd/GA catalyst, indicating the oxophilic property of Ni to assist formic acid oxidation via the bi-functional mechanism. The oxidation peak potential of 0.67 V was observed on PdNi/GA, about 40 mV less than that of Pd/C catalyst, indicating the merits of 3D structure of graphene. Moreover, PdNi/GA catalyst had the highest mass activity of 1699 mA•mg −1 compared to Pd/GA (851 mA•mg −1 ) and Pd/C (537 mA•mg −1 ) catalysts. The specific activity of PdNi/GA was 2.6 mA•cm −2 , which was 1.94 and 2.7 times of Pd/GA (1.34 mA•cm −2 ) and Pd/C (0.96 mA•cm −2 ) catalysts. The highly improved catalytic performance could be due to the combined alloy and support effect. The PdNi/GA was a promising catalyst for application in the direct formic acid fuel cells.

show abstract

Formic acid oxidation on AuPd core-shell electrocatalysts: Effect of surface electronic structure

Cited by 21 publications

References 72 publications

Enhanced Formic Acid Oxidation over SnO₂-decorated Pd Nanocubes

Enhanced Formic Acid Oxidation over SnO₂-decorated Pd Nanocubes

Highly coordinated Pd overlayers on nanoporous gold for efficient formic acid electro-oxidation

Formic Acid Electro-oxidation Catalyzed by PdNi/Graphene Aerogel

Contact Info

Product

Resources

About

Formic acid oxidation on AuPd core-shell electrocatalysts: Effect of surface electronic structure

Cited by 21 publications

References 72 publications

Enhanced Formic Acid Oxidation over SnO2-decorated Pd Nanocubes

Enhanced Formic Acid Oxidation over SnO2-decorated Pd Nanocubes

Highly coordinated Pd overlayers on nanoporous gold for efficient formic acid electro-oxidation

Formic Acid Electro-oxidation Catalyzed by PdNi/Graphene Aerogel

Contact Info

Product

Resources

About

Enhanced Formic Acid Oxidation over SnO₂-decorated Pd Nanocubes

Enhanced Formic Acid Oxidation over SnO₂-decorated Pd Nanocubes