Cadmium Sulfide Doping Boosts MXene Catalyst for Hydrogen Production

Researchers have synthesized a series of cadmium sulfide-doped Ti3C2Tx MXene nanocomposites and identified an optimal formulation for the electrocatalytic hydrogen evolution reaction (HER), a key process for producing clean hydrogen fuel from water. The work, published in Discover Chemical Engineering, reports that a composite containing 1 wt% CdS delivered the strongest catalytic performance among the materials tested.

The team, led by Ritu Raj, Mitali Hupele, Yalamarti Venkat Rajat Rao, Rajan Singh, Krishna Kanta Haldar and Gajendra Prasad Singh, prepared four composites, labeled MC1 through MC4, with CdS loadings ranging from 0.5 to 5 wt%. The materials were produced using a hydrothermal approach and evaluated as HER catalysts in a 0.5 M H2SO4 electrolyte, an acidic environment that is demanding for most catalysts.

Structural characterization supported the successful integration of CdS into the layered MXene host. X-ray diffraction confirmed the doping of CdS into the MXene structure, while Raman spectroscopy revealed systematic phonon shifts consistent with compressive in-plane strain. Transmission electron microscopy showed CdS nanoparticles anchored onto the Ti3C2Tx nanosheets, indicating intimate contact between the two components.

The interfacial loading proved critical to performance. Among the four composites, the sample with 1 wt% CdS, designated MC2, emerged as the optimal composition, suggesting that the balance between CdS coverage and MXene surface accessibility plays a decisive role in catalytic activity.

In electrochemical testing, MC2 recorded the lowest overpotential of the series, 310 mV at a current density of -10 mA/cm2, along with the smallest Tafel slope of 98 mV/dec. These values indicate that the composite requires less applied voltage to drive hydrogen generation and that its reaction kinetics are more favorable than those of the other samples tested.

MC2 also showed advantageous charge-transfer properties. Electrochemical impedance measurements yielded the lowest charge transfer resistance of the series, 152.2 ohms, alongside the highest mass activity of 48.90 A/g and the largest electrochemically active surface area, 38.625 cm2. A larger active surface area provides more sites where the hydrogen evolution reaction can take place, which helps explain the composite’s superior activity.

Durability is a central requirement for any practical electrocatalyst, and the optimized composite performed well in stability testing. MC2 maintained its activity over 2000 linear sweep voltammetry cycles, with only a negligible overpotential shift of 9.21 mV, indicating that the CdS-MXene interface remains functional under prolonged acidic operating conditions.

The authors position CdS-doped Ti3C2Tx MXene as a promising, cost-effective electrocatalyst for sustainable hydrogen production, drawing on the search for efficient catalysts made from earth-abundant elements rather than precious metals. Because the study reports performance in laboratory electrochemical testing in 0.5 M H2SO4, further work would be needed to establish how the material performs in operating devices and over longer timescales. The findings add to a growing body of research on MXene-based and transition-metal-doped catalysts for hydrogen evolution, a field that has seen recent reviews and related studies on heterojunction designs combining MXenes with other two-dimensional materials.

Subject of Research: Electrocatalytic hydrogen evolution using CdS-doped Ti3C2Tx MXene nanocomposites

Article Title: CdS-doped Ti3C2Tx MXene for efficient and stable electrocatalytic hydrogen evolution reaction

Article References: Raj, R., Hupele, M., Rao, Y. V. R., Singh, R., Haldar, K. K., & Singh, G. P. (2026). CdS-doped Ti3C2Tx MXene for efficient and stable electrocatalytic hydrogen evolution reaction. Discover Chemical Engineering. https://doi.org/10.1007/s43938-026-00145-9

Image Credits: AI Generated

DOI: 10.1007/s43938-026-00145-9

Keywords: MXene, Ti3C2Tx, CdS, hydrogen evolution reaction, electrocatalysis, nanocomposite, Tafel slope, overpotential, hydrothermal synthesis, green hydrogen, electrochemistry, CdS-doped