The decarbonization of power systems plays a great part in the carbon neutrality goal. Currently, researchers have explored reducing carbon in power systems in terms of the optimization of energy supply structure and operation strategies, but ignored the carbon reduction potential of users. To investigate the carbon reduction capability of users and further promote power system decarbonization through the active response of electricity loads, this paper proposes a carbon-reduction-oriented demand response (CRODR) technology based on generalized nodal carbon emission flow theory. First, the framework of the CRODR mechanism is established to provide an interaction baseline for users facing carbon reduction guiding signals. Secondly, the generalized nodal carbon emission flow theory is introduced to provide a calculation method for the guiding signals, considering dynamic electricity carbon emission factors with various spatiotemporal resolutions. Then, a matrix-based method is proposed to efficiently solve the carbon emission flow and obtain the guiding signals. On this basis, an optimal load-regulating model to help users meet their carbon reduction goals is built, and a carbon reduction benefit-evaluation method is proposed. Case studies on China’s national power system and a textile company verify that CRODR technology can realize efficient carbon reduction through load shifting while maintaining the total power consumption of users. The proposed CRODR technology is expected to provide a theoretical basis and guiding mechanism for promoting carbon reduction throughout the entire power system.

Precious metals exhibit promising potential for the hydrogen evolution reaction (HER), but their limited abundance restricts widespread utilization. Loading precious metal nanoparticles (NPs) on 2D/2D heterojunctions has garnered considerable interest since it saves precious metal consumption and facilitates unidirectional electron transmission from semiconductors to active sites. In this study, Ru NPs loaded on MXenes Mo₂C by an in-site simple strategy and then formed 2D/2D heterojunctions with 2D g-C₃N₄ (CN) via electrostatic self-assembly were used to enhance photocatalytic H₂ evolution. Evident from energy band structure analyses such as UV-vis and TRPL, trace amounts of Ru NPs as active sites significantly improve the efficiency of the hydrogen evolution reaction. More interestingly, MXene Mo₂C, as substrates for supporting Ru NPs, enriches photoexcited electrons from CN, thereby enhancing the unidirectional electron transmission. As a result, the combination of Ru-Mo₂C and CN constructs a composite heterojunction (Ru-Mo₂C@CN) that shows an improved H₂ production rate at 1776.4 μmol∙g⁻¹∙h⁻¹ (AQE 3.58% at 400 nm), which is facilitated by the unidirectional photogenerated electron transmission from the valence band on CN to the active sites on Ru (CN→Mo₂C→Ru). The study offers fresh perspectives on accelerated unidirectional photogenerated electron transmission and saved precious metal usage in photocatalytic systems.

Fair sharing of carbon emission responsibilities is an important direction for the low carbonization of power systems. This paper proposes a new low-carbon dispatch method (N-LCD), which takes node carbon emissions as a constraint for power system decision-making, so as to adapt to the current management needs of power carbon footprint. The N-LCD model is built on the traditional optimal power flow (OPF) or low-carbon dispatch (LCD) model, integrating carbon flow equations and constraints and introducing a bidirectional power flow component to solve the problem of unknown carbon flow direction in power flow optimization. Empirical analysis proves the effectiveness of the N-LCD model in ensuring the fair share of carbon emission responsibilities and solving low-carbon unit commitment optimization based on carbon nodal emission control.

Sustainable power-system operation requires carbon-reduction strategies that are emission-effective, physically deliverable, economically feasible, and compatible with user-side decarbonization claims. As Scope 2 carbon accounting increasingly emphasizes temporal, spatial, and physical consistency, dispatch models need to link user-level carbon claims with network-constrained power delivery. This paper proposes a User-Centric Carbon Cost-Constrained Low-Carbon Dispatch (CCC-LCD) framework that integrates carbon emission flow (CEF), nodal carbon intensity (NCI), network-constrained optimal dispatch, and endogenous demand response. A PTDF-based DC-OPF model represents active-power deliverability, while dual virtual flow variables determine carbon-flow directions endogenously. The model minimizes the target user’s physically traced Scope 2 emissions under a cost-tolerance budget and flexible-load constraints. Case studies on a modified IEEE 14-bus system show that nodal decarbonization is topology-dependent: high-load and high-NCI nodes obtain larger reductions from source-side generation substitution, whereas renewable-adjacent nodes exhibit limited marginal gains. The CEF-DR strategy outperforms single-mechanism cases, indicating the value of coordinating physical carbon-flow constraints with flexible demand. From a sustainability perspective, the proposed framework supports verifiable low-carbon electricity consumption, improves the economic feasibility of user-side decarbonization, and provides a practical dispatch tool for sustainable energy transition and corporate Scope 2 emission reduction.