Effect of nitrogen bubbles on electrochemical NRR performances. (a) Total electric charge and (b) FE for Pd/ACC at 0.1 V under various flow rates of N2. Chronoamperometry curves of Pd/ACC at 0.1 V with a gas flow rate of (c) 130 and (d) 50 sccm. Gas tube far from the electrode (red curve) and gas tube near the electrode (blue curve). (e) Total electric charges and FEs and (f) average NH3 yield rates for Pd/ACC at 0.1 V for 2 h by changing the gas flow rate and the position of the gas tube. (g) FEs and average NH3 yield rates for (g) Ir/ACC and (h) RuPd/ACC at 0.1 V for 2 h by changing the gas flow rate and the position of the gas tube.