| Autor: |
Theerthagiri J; Centre of Excellence for Energy Research , Sathyabama Institute of Science and Technology (Deemed to be University) , Chennai 600119 , India., Cardoso ESF; Institute of Chemistry , Universidade Federal de Mato Grosso do Sul , Senador Filinto Muller Avenue, 1555 , Campo Grande , Mato Grosso do Sul 79074-460 , Brazil., Fortunato GV; Institute of Chemistry , Universidade Federal de Mato Grosso do Sul , Senador Filinto Muller Avenue, 1555 , Campo Grande , Mato Grosso do Sul 79074-460 , Brazil., Casagrande GA; Institute of Chemistry , Universidade Federal de Mato Grosso do Sul , Senador Filinto Muller Avenue, 1555 , Campo Grande , Mato Grosso do Sul 79074-460 , Brazil., Senthilkumar B; Materials Research Centre , Indian Institute of Science , Bangalore 560012 , India., Madhavan J; Solar Energy Lab, Department of Chemistry , Thiruvalluvar University , Vellore 632115 , Tamil Nadu , India., Maia G; Institute of Chemistry , Universidade Federal de Mato Grosso do Sul , Senador Filinto Muller Avenue, 1555 , Campo Grande , Mato Grosso do Sul 79074-460 , Brazil. |
| Abstrakt: |
Robust electrocatalysts toward the resourceful and sustainable generation of hydrogen by splitting of water via electrocatalytic hydrogen evolution reaction (HER) are a prerequisite to realize high-efficiency energy research. Highly electroactive catalysts for hydrogen production with ultralow loading of platinum (Pt) have been under exhaustive exploration to make them cutting-edge and cost-effectively reasonable for water splitting. Herein, we report the synthesis of hierarchically structured nickel pyrophosphate (β-Ni 2 P 2 O 7 ) by a precipitation method and nickel phosphate (Ni 3 (PO 4 ) 2 ) by two different synthetic routes, namely, simple cost-effective precipitation and solution combustion processes. Thereafter, Pt-decorated nickel pyrophosphate and nickel phosphate (β-Ni 2 P 2 O 7 /Pt and Ni 3 (PO 4 ) 2 /Pt) were prepared by using potassium hexachloroplatinate and ascorbic acid. The fabricated novel nickel pyrophosphate and nickel phosphate/Pt materials were utilized as potential and affordable electrocatalysts for HER by water splitting. The detailed electrochemical studies revealed that the β-Ni 2 P 2 O 7 /Pt (1 μg·cm -2 Pt) electrocatalyst showed excellent electrocatalytic performances for HER in acidic solution with an overpotential of 28 mV at -10 mA·cm -2 , a Tafel slope of 32 mV·dec, and an exchange current density ( j 0 ) of -1.31 mA·cm -2 , which were close to the values obtained using the Vulcan/Pt (8.0 μg·cm -2 Pt), commercial benchmarking electrocatalyst with eight times higher Pt amount. Furthermore, the β-Ni 2 P 2 O 7 /Pt electrocatalyst maintains an excellent stability for over -0.1 V versus RHE for 12 days, keeping j 0 equal after the stability test (-1.28 mA cm -2 ). Very well-distributed Pt NPs inside the "cages" on the β-Ni 2 P 2 O 7 structure with a crystalline pattern of 0.67 nm distance to the Ni 2 P 2 O 7 /Pt electrocatalyst, helping the Volmer-Tafel mechanism with the Tafel reaction as a major rate-limiting step, help to liberate very fast the Pt sites after HER. The high electrocatalytic performance and remarkable durability showed the β-Ni 2 P 2 O 7 /Pt material to be a promising cost-effective electrocatalyst for hydrogen production. |
