Exploring the relationship between urban polycentric structure and green total factor productivity in China: Insights from urban development patterns and scale borrowing

Rapid urbanization has driven urban structure transformation and posed both opportunities and challenges for achieving high-quality economic growth. This study investigates the impact of urban polycentric structures (POLY) on green total factor productivity (GTFP) in China, innovatively highlights the mediating effect of scale borrowing and the moderating effect of urban development patterns. Results show that POLY has positive impacts on GTFP, and such promotion effect grows as GTFP increases. Scale borrowing plays a mediating role and different urban development patterns have various moderating effects. Specifically, urban expansion strengthens the positive moderating role of scale borrowing, whereas urban shrinkage weakens it. The threshold effect and heterogeneity analysis reveal that the positive impact of POLY on GTFP becomes more pronounced in cities with abundant land and population resources. In addition, POLY has positive spatial spillover effects, as its influence extends beyond individual cities and benefits neighboring areas. By integrating spatial structure, scale borrowing, and urban development patterns into one framework of economic growth, this study contributes to a novel understanding of high-quality economic development and sustainable urban structural transformation for policymakers.