Uniting for a Sustainable Future: Exploring the spatial spillover effect of intercity innovation collaboration on carbon emission performance in China

Under the dual-carbon background, it has become crucial to promote green and low-carbon development through regional collaboration. Based on the panel data covering 248 cities in China from 2001 to 2022, this study first examines the spatiotemporal evolution patterns of intercity innovation collaboration (IIC) and carbon emission performance (CEP), and then uses the spatial Durbin model (SDM) to investigate the impact and mechanisms of intercity innovation collaboration on carbon emission performance. Results show that China’s intercity innovation collaboration and carbon emission performance have achieved significant growth Since 2001, The former has shown a multi-center structure centered on regional hub cities, while the latter has shown obvious spatial agglomeration. SDM estimates indicate that intercity innovation collaboration has a significant positive impact and spatial spillover effect on carbon emission performance. This conclusion remains valid after endogeneity tests and multidimensional robustness checks, while its impact intensity and spillover effects vary significantly across urban characteristics. Mechanism analysis reveals that intercity innovation collaboration has improved carbon emission performance of local and neighboring cities, by combining endogenous drivers of green technological progress and industrial structure optimization with the external incentive of innovation services deepening. In addition, digital infrastructure strengthens the positive impact of intercity innovation collaboration on local carbon emission performance, but it has not generated a positive spillover on the surrounding areas. These findings provide an important theoretical basis and empirical evidence for the establishment of a cross-regional green innovation system and the design of spatially differentiated collaborative governance policies. • Uncovered the environmental spillover effects of IIC. • Both IIC and CEP have improved substantially since the early 21st century. • IIC can enhance CEP in both local and neighboring cities. • The mechanism of IIC on CEP was analyzed. • Digital infrastructure plays an asymmetric moderating role on this relationship.