Abstract Noble metal Pt is usually employed as the effective catalyst for HCHO oxidation and counter electrode (CE) of dye-sensitized solar cell (DSSC), but its low reserve and high cost inspire the exploration of more efficient and low-cost alternatives. In this study, first, Co3O4 porous nanobelts were directly grown on compacted stainless steel mesh (CSSM) by simple hydrothermal method with post heat-treatment. Due to the synergistic effect of Co3O4 and flexible substrate, this immobilized Co3O4 exhibited stronger catalytic activity and stability for HCHO oxidation compared to powdered Co3O4 with similar morphology; Second, the immobilized Co3O4 film was converted to Co3O4@Co3S4 porous nanobelts film via in-situ sulfurization reaction for various periods. The obtained Co3O4@Co3S4 was used as the CE of flexible DSSCs, and a maximum power conversion efficiency of 5.30% was achieved, which was higher than that of the DSSC with a sputtered Pt CE (5.23%). Furthermore, the FDSSCs using this CE still preserved over 93% of its initial conversion efficiency after consecutive bending tests with different angles and 15-day aging test. The excellent electrocatalytic activity, mechanical and long-term stability and low material cost of the optimized Co3O4@Co3S4 electrode provide it with promising potential application as CE of FDSSCs.

中文翻译：

---

用于 HCHO 催化氧化的压实不锈钢网状 Co3O4 多孔纳米带和通过原位硫化的 Co3O4@Co3S4 作为柔性染料敏化太阳能电池的无铂对电极

摘要 贵金属Pt通常被用作染料敏化太阳能电池（DSSC）的HCHO氧化和对电极（CE）的有效催化剂，但其低储量和高成本激发了对更高效和低成本替代品的探索。在这项研究中，首先，通过简单的水热法和后热处理，在压实的不锈钢网（CSSM）上直接生长 Co3O4 多孔纳米带。由于Co3O4和柔性基材的协同作用，与形貌相似的粉末状Co3O4相比，这种固定化的Co3O4对HCHO氧化表现出更强的催化活性和稳定性；其次，固定化的 Co3O4 薄膜通过不同时期的原位硫化反应转化为 Co3O4@Co3S4 多孔纳米带薄膜。获得的 Co3O4@Co3S4 用作柔性 DSSCs 的 CE，并且实现了 5.30% 的最大功率转换效率，高于具有溅射 Pt CE 的 DSSC（5.23%）。此外，使用该 CE 的 FDSSC 在连续不同角度弯曲测试和 15 天老化测试后仍保持其初始转换效率的 93% 以上。优化后的 Co3O4@Co3S4 电极优异的电催化活性、机械和长期稳定性以及较低的材料成本，使其作为 FDSSC 的 CE 具有广阔的应用前景。