TY - JOUR
T1 - Synergistic Coupling of a Molybdenum Carbide Nanosphere with Pt Nanoparticles for Enhanced Ammonia Electro-Oxidation Activity in Alkaline Media
AU - Bayati, Maryam
AU - Liu, Xiaoteng
AU - Abellan, Patricia
AU - Pocock, Dan
AU - Dixon, Michael
AU - Scott, Keith
PY - 2020/1/27
Y1 - 2020/1/27
N2 - Ammonia will play a pivotal role in the future of zero carbon emitted sustainable fuel. The development of inexpensive efficient catalysts for ammonia electro-oxidation (AEO) is essential to its success. This study provides evidence that nanoparticles of earth-abundant elements, e.g., MoC, encapsulated in a doped-graphene shell (DG-MoC), are promising cocatalysts of Pt for AEO which significantly improve the catalyst cost and activity in comparison to the state-of-the-art platinum. DG-MoC, DG-MoC-supported Pt (Pt/DG-MoC), and nitrogen-doped-graphene (NG) catalysts were synthesized and characterized by Brunauer–Emmett–Teller (BET) surface area analysis, electrochemical techniques, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX), scanning transmission electron microscopy (STEM), and electron energy loss (EEL) spectroscopy. The XRD analysis of DG-MoC disclosed that the presence of α-MoC1–x microscopy techniques demonstrates a close vicinity of Pt and MoC nanoparticles in Pt/DG-MoC. We report, for the first time, that Pt/DG-MoC particles reveal a large synergistic effect for AEO activity, while DG-MoC and NG showed no activity. Pt/DG-MoC gave a higher current density, lower half- and peak- potentials (28 mV and 14 mV, respectively), and greater resilience to ammonia poisoning than Pt/C as shown in the fall in the peak current density in the second voltammogram, i.e, approximately 3.6% compared to 20.7% for Pt/C. The XPS spectrum of the catalysts explained the source of this synergistic effect.
AB - Ammonia will play a pivotal role in the future of zero carbon emitted sustainable fuel. The development of inexpensive efficient catalysts for ammonia electro-oxidation (AEO) is essential to its success. This study provides evidence that nanoparticles of earth-abundant elements, e.g., MoC, encapsulated in a doped-graphene shell (DG-MoC), are promising cocatalysts of Pt for AEO which significantly improve the catalyst cost and activity in comparison to the state-of-the-art platinum. DG-MoC, DG-MoC-supported Pt (Pt/DG-MoC), and nitrogen-doped-graphene (NG) catalysts were synthesized and characterized by Brunauer–Emmett–Teller (BET) surface area analysis, electrochemical techniques, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX), scanning transmission electron microscopy (STEM), and electron energy loss (EEL) spectroscopy. The XRD analysis of DG-MoC disclosed that the presence of α-MoC1–x microscopy techniques demonstrates a close vicinity of Pt and MoC nanoparticles in Pt/DG-MoC. We report, for the first time, that Pt/DG-MoC particles reveal a large synergistic effect for AEO activity, while DG-MoC and NG showed no activity. Pt/DG-MoC gave a higher current density, lower half- and peak- potentials (28 mV and 14 mV, respectively), and greater resilience to ammonia poisoning than Pt/C as shown in the fall in the peak current density in the second voltammogram, i.e, approximately 3.6% compared to 20.7% for Pt/C. The XPS spectrum of the catalysts explained the source of this synergistic effect.
KW - ammonia electro-oxidation
KW - fuel cell
KW - molybdenum carbide
KW - platinum nanoparticles
KW - synergistic effect
UR - http://www.scopus.com/inward/record.url?scp=85078490541&partnerID=8YFLogxK
U2 - 10.1021/acsaem.9b01979
DO - 10.1021/acsaem.9b01979
M3 - Article
SN - 2574-0962
VL - 3
SP - 843
EP - 851
JO - ACS Applied Energy Materials
JF - ACS Applied Energy Materials
IS - 1
ER -