A digital path to carbon neutrality: Heterogeneous green innovations and their spatial impact for Chinese cities

With the accelerating growth of the digital economy, digital technology—as a type of general-purpose technology—creates a more inclusive and open environment for innovation, thereby facilitating the shift toward a low-carbon economy by promoting green innovation. However, we know little about whether there are differences in the roles of various types of green innovation. Therefore, this study evaluates the impact of DE on low-carbon development (LCD) through heterogeneous green innovation. The results show that DE has a significant nonlinear effect on LCD, with an initial suppressing effect that turns positive and strengthens as DE develops. Green innovation is a crucial mechanism through which DE promotes LCD. Moreover, compared to other types of green innovation, invention green innovation, source-control green innovation, and enterprise green innovation play a more significant role in this process. From a spatial perspective, the spillover effect of DE on LCD of neighbouring cities exhibits a shift from a “neighbour-beggar” to a “neighbour-companion” dynamic, demonstrating a U-shaped change. This spillover effect diminishes as geographic distance increases and is significant only within a range of 100–400 km. The green innovation spillover is a key mechanism driving this U-shaped transformation. Our findings offer valuable theoretical and practical insights for other developing countries undergoing a low-carbon transition. • This study explores how digital economy influences low-carbon development (LCD) through heterogeneous green innovation. • It identifies a nonlinear relationship between digital economy development and LCD. • The 3SLS method is employed to test the mediating role of green innovation in the DE-LCD link. • Invention-based, source-control, and enterprise-led green innovations are identified as key mediators. • A U-shaped spatial spillover effect of DE on neighbouring cities' LCD is observed.