Table 1. Statistical Parameters of the Catalysts Derived via Chemical and Solvothermal Reduction.

synthesis	chemical reduction				solvothermal reduction
parameter	Ni/C	Ni3Fe/C	Ni3Co/C	Ni3Cu/C	Ni/C	Ni3Fe/C	Ni3Co/C	Ni3Cu/C
L (nm)a	1.5	1.4	1.1	1.3	5.1	10.0	10.8	9.2
Δd (nm)b	3–19	3–33	3–61	3–26	4–12	10–18	7–43	9–25
dav (nm)c	11 ± 3	15 ± 3	23 ± 3	14 ± 3	8 ± 3	14 ± 3	21 ± 3	17 ± 3
STEM (m2 gNi–1)d	63	45	29	50	84	50	32	39

^aCrystallite size calculated from the Scherrer equation for the XRD diffraction peak for Ni(111): L = Kλ/β cos θ, where K ∼ 0.9 is a shape factor, λ is the wavelength for Cu Kα radiation, β is the full width at half-maximum (fwhm, in radians), and θ is the Bragg angle (in radians).

^bΔd: range of particle diameters based on the TEM image analysis.

^cd_av: average diameter calculated using the equation .

^dS_TEM: total surface area calculated based on the TEM images using the equation ; ; N: number of particles; S_i: surface of all the particles with the diameter d_i; ρ = 8.9 × 10⁶ g m^–3 (density of Ni); w_i: mass fraction of the particles with the diameter d_i; N_i: number of particles with the diameter d_i; m_i: mass of one particle with the diameter d_i..