Molybdenum-Tungsten carbides based electrocatalysts for hydrogen evolution reaction

Figures & data

Figure 1. XRD patterns of (a) Ni-WC, Co-WC and NiCo-WC; (b) Ni-MoC, Co-MoC and NiCo-MoC.

Table 1. Estimated crystallite sizes and lattice strains of the transition metal carbides.

Material	Crystallite size D (nm)	Strain ϵ
Ni-WC	73	0.00135
Co-WC	64	0.00141
NiCo-WC	59	0.000457
Ni-MoC	52	0.000368
Co-MoC	53	0.000622
NiCo-MoC	44	0.00185

Figure 2. SEM images and EDS spectra of Ni-WC (a, d), Co-WC (b, e), NiCo-WC (c, f), Ni-MoC (g, j), Co-MoC (h, k), NiCo-MoC (i, l).

Figure 3. High-resolution XPS spectra of C 1s, Ni 2p and Co 2p, Mo 3d and W 4f.

Figure 4. Multiple scans of the CVs of the modified TiO₂ electrodes in 1.0 M NaOH solution.

Figure 5. Polarisation curves of the (a) WC-based and (b) MoC-based electrocatalysts.

Table 2. Electrocatalytic parameters of the studied electrocatalysts for HER.

Sample	Voltage (in V) at 10 mA cm^−2	Tafel slope (mV dec^−1)
TiO2	1.470	168
Pt/C	1.425	179
Ni-WC	1.420	135
Co-WC	1.442	156
NiCo-WC	1.458	169
Ni-MoC	1.422	161
Co-MoC	1.508	162
NiCo-MoC	1.473	169

Figure 6. Tafel plots of the (a) WC- based and (b) MoC-based electrocatalysts.

Figure 7. Catalytic durability curves of (a) WC- based and (b) MoC-based electrocatalysts.