Impact of Digital Green Finance on New Quality Productivity from the Perspective of Spatial Spillover: Evidence from 285 Cities in China

Digital green finance (DGF) is the core driving force for promoting high-quality economic development, but it is worth exploring whether it can provide support for the development of urban new quality productivity (NQP). This study selects panel data from 285 prefecture-level and above cities in China spanning 2009–2023 to measure the levels of NQP and DGF using the entropy method and the coupling coordination index model, and explores the spatial spillover effects of DGF on the development of urban NQP and its underlying mechanisms by constructing a spatial Durbin model and a mediation effect model. The results indicates that both the levels of urban DGF and NQP in China are on an upward trajectory, exhibiting a "high-high and low-low" spatial clustering characteristics. DGF significantly empowers the development of urban NQP, with notable spatial spillover effects. Furthermore, DGF promotes the development of NQP by driving green technological innovation and industrial structure upgrading, and the intermediary effect of industrial structure upgrading is more obvious. In addition, regional heterogeneity, urban agglomeration heterogeneity, and temporal heterogeneity in the issuance of the "Guidance on Building a Green Financial System" significantly influence the effectiveness of DGF. Accordingly, it is recommended to strengthen the policy support system for DGF, establish a collaborative development mechanism of DGF, and enhance green technology innovation and industrial structure upgrading, as well as implement differentiated regional strategies. These measures will provide robust support for unleashing the potential of DGF in boosting NQP.