It is of emerging interest to convert CO2 and green H2 into solar fuels with great efficiency through photothermal CO2 hydrogenation. However, designing photothermal catalysts with improved sunlight harvesting ability, intrinsic catalytic activity, and thermal management to prevent heat dissipation still remains rather challenging. Herein, we report a facile structural engineering strategy for preparing efficient nanoarray-based photothermal catalysts with strong light absorption ability, high metal dispersity, and effective thermal management. Optimizing the 120 μm-SiNCs@Co catalyst allowed it to reach a record high Co-based photothermal CO2 conversion rate of 1780 mmol gCo-1 h-1. This study provides insight into the structural engineering of photothermal catalysts for enhanced catalytic performance and lays a foundation for efficient photothermal CO2 catalysis.