Plastic waste is one of the most pressing environmental challenges of our time. While recycling technologies continue to improve, most current methods either downcycle plastics into lower-value products or require energy-intensive chemical processes. Electrocatalytic upcycling has emerged as a promising alternative, using electricity to transform plastic-derived molecules into valuable chemicals under mild conditions.
However, conventional electrochemical systems suffer from a fundamental limitation: the two electrodes typically produce different products. The anodic reaction may convert plastic waste into one chemical, while the cathodic reaction produces hydrogen or another unrelated product. This mismatch complicates product separation, reduces overall efficiency, and limits economic viability.
A research team led by Zhijie Chen, Bing-Jie Ni, and Kai Yan has now overcome this challenge by designing a “dual-side electrosynthesis” strategy, in which both electrodes are engineered to generate the same high-value product: succinic acid.
Succinic acid is a versatile four-carbon platform chemical widely used in the manufacture of biodegradable polymers, solvents, food additives, and pharmaceutical intermediates. It has been recognized as one of the most important bio-based chemicals for building a sustainable chemical industry.
In the new system, waste polybutylene terephthalate (PBT), commonly used in textiles and engineering plastics, is hydrolyzed to produce 1,4-Butanediol. This molecule is then selectively oxidized at the anode using a specially designed NiCoAl Layered Double Hydroxide catalyst. The catalyst achieves a succinic acid selectivity of 96.5% and a Faradaic efficiency of 97.9%, while maintaining excellent stability over 120 hours of operation.
At the cathode, biomass-derived Maleic Acid is electrochemically reduced to the same product using a PdPtSn Alloy catalyst. This synchronized conversion means that both electrodes contribute directly to succinic acid production.
When implemented in a continuous-flow electrolyzer, the dual-side system achieved an apparent succinic acid yield of 169.1%, exceeding the theoretical limit of a conventional single-electrode process. This remarkable result demonstrates that carbon from two independent waste streams, plastic waste and biowaste, can be simultaneously funneled into one unified product stream.
Advanced theoretical calculations revealed why the anode catalyst performs so well. Incorporation of cobalt alters the electronic structure of nickel, strengthening its interaction with oxygen-containing intermediates and lowering the energy barrier for selective oxidation of 1,4-butanediol. This rational catalyst design significantly enhances both activity and selectivity.
Beyond its technical performance, the process also shows strong commercial promise. Techno-economic analysis estimated a net profit of approximately US$1,076 per ton of succinic acid produced, highlighting the economic feasibility of this integrated circular manufacturing approach.
According to the researchers, the significance of this work extends far beyond succinic acid production. The concept of product-convergent electrosynthesis offers a new design principle for electrochemical manufacturing, enabling multiple waste streams to be transformed into a single target chemical with unprecedented efficiency.
This breakthrough provides a powerful example of how renewable electricity can be used to close material loops and create value from waste. By integrating plastic recycling, biomass valorization, and green chemical synthesis into one platform, the technology opens new opportunities for sustainable manufacturing and a truly circular economy.
Science Bulletin
Experimental study