Figure 4.

In situ FTIR spectra of (a) N₂ activation and adsorption (in N₂ plasma, Q_gas = 40 mL/min) and (b) hydrogenation of the adsorbed N₂ (in an H₂ plasma, Q_gas = 40 mL/min) at 5 min of discharge time. (c) IR spectra of plasma-assisted ammonia synthesis (discharge time = 15 min, Q_gas = 40 mL/min, N₂/H₂ = 1:3, full scale as shown in Figure S17) on MCM-41, Ni/MCM-in, and Ni/MCM-out, respectively. (d) N 1s XPS profiles of the spent catalysts and MCM-41 after the reaction. (e) Normalized relative intensities of N, H_α, and NH peaks as measured by optical emission spectrometry (SEI = 24 kJ/L, 35 °C, 1 bar, full scale as shown in Figure S20a) (Errors were obtained from three tests under the same conditions).