To realize highly efficient utilization of solar energy for solving problems of environmental pollution and energy shortage has attracted increasing attention. Herein, a two-step exfoliation-restacking process was employed to construct ultrathin Z-scheme two-dimensional (2D)/2D N-doped HTiNbO5 nanosheets/gC(3)N(4) (RTCN) heterojunction composites with the increased specific surface areas, showing the enhanced photocatalytic performance for rhodamine B (RhB) degradation and hydrogen (H-2) generation under visible light irradiation. A 2D/2D heterojunction structure was formed between N-doped H.-restacked HTiNbO5 nanosheets (N-RTNS) and g-C3N4, which was beneficial for the effectively spatial separation of photogenerated charge carriers. The improved photocatalytic activities may be attributed to the synergistic effects of the increased specific surface area, N-doping and 2D/2D heterostructure. The active species of holes (h(+)), hydroxyl (center dot OH) and superoxide (center dot O-2(-)) radicals contributed to RhB photodegradation. A Z-scheme photocatalytic mechanism was proposed over RTCN-2 composite, showing dual advantages of the highly redox ability and efficient charge carrier separation. (C) 2020 Elsevier Inc. All rights reserved.