2.1. Green Innovation
In the context of the “two-carbon” goal, green innovation, as an important activity to promote sustainable environmental development, has received extensive attention from scholars. A review of the existing research finds that the factors affecting the green innovation of enterprises are mainly concentrated in two aspects: environmental effects and resource supply. In terms of environmental effects, Lyubich et al. believe that when companies face higher environmental standards, they will be more inclined to develop and apply clean technologies to reduce the environmental pollution caused by their productions and operations and implement environmental regulations such as environmental taxes [
9]. It is an effective way to improve environmental standards. Yu Lianchao et al. found that environmental taxes can effectively promote the green innovation of enterprises [
10], which verifies the views of Lyubich et al. Furthermore, environmental regulations represented by taxes stimulate the green innovation of enterprises, and the incentive effect varies by differences in types of firms and regions [
11]. The above research shows that scientific and reasonable environmental regulations and the policy mix can actively guide and motivate enterprises to carry out green technology innovation [
12]. In addition to the abovementioned mandatory environmental effects, incentive-based environmental measures also have a positive impact on green innovation [
11], such as government subsidies and some voluntary agreements [
13,
14]. In terms of resource supply, green innovation is characterized by high investments, long cycles, and high benefit uncertainty compared with other innovation activities and requires greater resource investment [
15]. Green innovation resources, such as FDI, environmental investment, and foreign investment, have a positive impact on green innovation behavior and efficiency [
16,
17], and if the green loan interest rate provided by banks is lower than the threshold, enterprises tend to accept bank loans to implement green innovation [
18]. In addition, corporate financial and governance status is also a cornerstone of green innovation resources. Good finance can provide sufficient material and human resources for green innovation [
19]. The environmental protection orientation of corporate stakeholders and equity financing are also conducive to green innovation [
20,
21].
2.2. Digital Financial Inclusion
As an important engine for the country’s high-quality development, digital inclusive finance provides new impetus and opportunities for promoting economic development [
22], and its stable development has important macro and micro impacts. At the macro level, the development of digital inclusive finance has positive significance for promoting entrepreneurship, stimulating residents’ consumption, accelerating inclusive growth, narrowing the urban-rural income gap, and driving the digital innovation of commercial banks [
23,
24,
25,
26,
27]. At the microlevel, digital inclusive finance can, on the one hand, carry out an accurate risk assessment for enterprises under conditions of digital technology [
28] and, on the other hand, enhance the information processing capabilities of financial institutions and investors, effectively reducing the relationship between enterprises and the market. The problem of information asymmetry between enterprises [
29] increases the source channels and availability of funds for enterprises, thereby easing their financing constraints. In addition, some scholars have paid attention to the significant impact of digital financial inclusion on corporate innovation. The development of digital inclusive finance can alleviate the financing constraints and financial mismatches faced by enterprises and promote enterprise innovation through R&D investment, the accumulation of redundant expansion effects, and human capital upgrade effects [
29,
30,
31].
2.3. Digital Financial Inclusion and Green Innovation
A large number of studies have shown that digital financial inclusion has a positive impact on corporate innovation activities, investment, and income [
29,
32]. Specifically, from the perspective of green innovation, the development of digital finance promotes urban economic agglomeration and optimizes the regional financial structure, provides a good external financial environment for the development of enterprises’ green innovations, eases the financing constraints faced by enterprises [
33], and then promotes enterprises’ green innovations [
34]. Jiang Jianxun et al. proved this conclusion from the perspective of new energy enterprises [
35]. Based on the above research, we believe that the development of digital financial inclusion has a similar positive effect on the green innovation of heavy-polluting enterprises.
The Porter hypothesis proposes that innovation can offset the cost of complying with environmental requirements, and when the environmental system can be improved, it can further guide enterprises toward innovation. The mainstream view holds that both mandatory and incentive environmental effects can have a positive impact on corporate green innovation [
10,
14]. Currently, however, for heavily polluting enterprises mainly concentrated in the manufacturing sector, green innovation is closely related to capital market opening [
36], resource acquisition and input [
16], and the Green Credit System is formulated for the sustainable development of the environment and the transformation of green development of enterprises. The implementation of green credit policies, such as the “Guidelines”, has changed the external credit environment, making it more difficult to obtain loans and increasing the financing constraints of such enterprises [
37]. In addition, there is currently no complete green innovation mechanism in China to ensure that enterprises obtain public resources. Due to the nature of the industry, it is relatively difficult for heavily polluting enterprises to obtain public resources, such as government subsidies, which also deepens the financing constraints and weakens the incentive to engage in green innovation and, thus, is not conducive to the green innovation output of heavily polluting enterprises [
38]. According to the theory of resource allocation efficiency, however, the limited financial capital in the market should flow into high-efficiency enterprises to achieve the overall effective allocation of resources and Pareto optimality, the misallocation of financial resources is a deviation from “effective allocation” [
30]. The external financing that heavily polluting enterprises can obtain is limited. The main financing methods come from bond financing provided by financial institutions such as banks and equity financing in the capital market [
39]. This type of financing not only pays more attention to the ability of enterprises to obtain profits and competitive advantages but also considers whether the funds can be recovered safely and whether the loan income is higher than the cost, including time value, etc., and is also affected by policy bias. Economic development allocates more financial resources to projects with quick returns and short cycles, while green innovation and development are characterized by long cycles, high costs, unclear market demands, and uncertain returns, making them vulnerable to misallocation of financial resources [
30].
The financial environment is one of the main factors affecting the business activities of enterprises, and the supply of financial resources significantly affects the progress of business activities [
40]. Compared with the “backward-looking” preference of the traditional credit model, the development of digital inclusive finance has effectively corrected the “stage mismatch” in the traditional financial system, making it easier for enterprises to obtain financial resources than before; that is, the development of digital inclusive finance can hedge financing. The “financial dilemma” was brought about by constraints [
41]. First, the issue of information asymmetry is a leading problem that results in corporate financing constraints. Digital financial inclusion can reduce the information asymmetry between investors and companies by virtue of its digital technology [
42]. Furthermore, digital inclusive finance makes up for the under covered long-tail groups in the traditional financial model and incorporates small and medium-sized enterprises, individual industrial and commercial households, and individual investors who are not able to participate in investment under the traditional financial model into the new financial system. It increases the investor group and broadens the source of funds, which effectively alleviates the problem of corporate financing constraints [
29]. Second, digital inclusive finance improves the ability of information collection and integration. Through the capture and analysis of corporate behavioral data, it is possible to conduct more accurate risk assessments for enterprises and then strengthen the control of risks and credit, thus, forcing traditional transformation and upgrading of financial institutions to alleviate the misallocation of financial resources and improve the supply efficiency of financial resources [
30]. Third, digital inclusive finance relies on its artificial intelligence technology, big data technology, machine learning technology, and other emerging technologies to make the production and operation of heavily polluting enterprises more scientific and efficient. It also contributes to the organizational structure becoming more rational and flexible, thereby reducing the cost of enterprises and expenses to provide more capital space for green innovation and ensure the smooth progress of green innovation of enterprises [
31]. Based on the above analysis, the following hypothesis is proposed:
Hypothesis 1a (H1a). Digital financial inclusion effectively promotes green innovation in enterprises.
Hypothesis 1b (H1b). Digital inclusive finance promotes the green innovation of enterprises by reducing the financing constraints and financial mismatches faced by enterprises.