Oxygen plasma and cation tuning in Ni2P for water oxidation

• Main Author: Lew, Wai Sing
• Other Authors: Alex Yan Qingyu
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Materials
• Online Access: http://hdl.handle.net/10356/77364
• Institution: Nanyang Technological University

With the continual increase demand for renewable sources of energy, hydrogen has been identified to be one of the most promising sources of energy. Oxygen evolution reaction (OER) from water splitting is thermodynamically unfavourable and sluggish in kinetics compared to the other half (hydrogen evolution reaction, HER). A highly efficient and low cost electrocatalyst is therefore in great demand. Herein, we developed an exceptionally efficient OER electrocatalyst by using core nickel(II) phosphide Ni2P via a series of cation tuning and surface engineering. Interestingly, remarkable results have been shown from the theoretical calculations made through modifications of selective doping of Vanadium together with plasma treatment using oxygen, which increases the overall number of available states at Fermi-level and inproves the overall adsorption of OH− in the Ni sites. The performance is further exploited with the use of oxygen plasma treatment which enhances hydrophilicity of KOH solution, resulting in a contact angle of 44.95° down to 16.8°. This is evidenced by a high BET surface area, which is the result of higher active sites available and lower overall charge transfer resistance. Furthermore, results have shown that the synthesised catalyst has an OER overpotentials of 257 mV at current density of 10 mA cm−2 with a Tafel slope of 43.5 mV dec−1 in 1M KOH. The performance is very much similar to that of noble metals. Thus, the presented work opens a new way in overcoming the high cost and scarcity of using noble metals as electrocatalyst.