Ammonia synthesis via the electrochemical method is an environmentally-friendly alternative to the Haber-Bosch process. In this work, carbon materials made from fresh cigarette filters were used as the working electrode for the electrochemical synthesis of ammonia. TiO2 was found to exist in the hydrochar of cigarette filters with a mass loading of 0.8 wt%, and showed positive impact on the catalytic performance of the hydrochar. A decent NH3 yield of 6.02 mu g mg(cat.)(-1) h(-1) and a FE of 8.96% were achieved at -0.1 V versus reversible hydrogen electrode (RHE) in N-2 -saturated 0.05 M H2SO4. The design of experiments proved that TiO2, which was contained in the hydrochar, indeed played a great role in the catalytic reaction of ammonia synthesis. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.