Synergistic Catalyst Design for Enhanced Electrochemical Hydrogen Evolution: Fe<sub>2</sub>O<sub>3</sub>/MoS<sub>2</sub>/Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene Ternary Composite
Sumanth Dongre S, Asif Iqbal, Ranjit Thapa, M Pratheeksha, R. Shwetharani, R. Geetha Balakrishna
Abstract
Developing a cost-effective and earth-abundant electrocatalyst to produce green hydrogen is vital toward sustainable energy with a net-zero carbon emission. In this regard, abundantly available nanostructured transition metals with a tunable structure, high surface area, and high conductivity are considered to be suitable cathode materials for water splitting. Herein, we design a 3D/2D Fe 2 O 3 /MoS 2 /Ti 3 C 2 T x MXene ternary composite through hydrothermal synthesis for electrochemical hydrogen evolution. The 3D/2D composite of Fe 2 O 3 nanoparticles with MoS 2 nanosheets showed exceptional electrocatalytic activity with an overpotential and a Tafel slope of 194.1 mV and 102 mV/dec, respectively, which outperforms pristine Fe 2 O 3 nanoparticles and MoS 2 nanosheets by a great margin of over 50 mV. To further enhance the electrical conductivity, exfoliated Ti 3 C 2 T x MXene is introduced to form a ternary composite, and it is found that this composite electrocatalyst shows an impressive overpotential of 123 mV at a current density of 10 mA/cm 2 in an acidic medium, with high durability over 12 h for hydrogen evolution. The smaller charge-transfer resistance (88.2 Ω) and larger double-layer capacitance (12 mF/cm 2 ) values of the ternary composite with a low Tafel slope of 71 mV/dec indicate the role of enhanced interfacial charge transfer and specific surface area inducing enhanced HER activity.