Comprehensive experimental design for the preparation and performance exploration of BiVO₄ driven by micro-projects

Experimental teaching in materials chemistry is central to developing students’ research literacy and practical competence. In the context of emerging engineering education, conventional laboratory instruction exhibits three major limitations: fragmentation of synthesis, characterization, and performance evaluation (impeding systematic understanding of structure–property relationships); outdated content with insufficient coverage of advanced functional materials; and overly prescriptive protocols that constrain independent inquiry and innovation. To address these issues, this study adopts the visible-light-responsive material BiVO₄ as a model system and develops a micro-project-driven teaching framework that integrates discrete experimental components into a coherent, progressive task chain.

Because the crystal phase of BiVO₄ is highly sensitive to hydrothermal temperature, a teaching model based on single-variable open inquiry and parallel multigroup collaboration was established. Low-toxicity precursors and the biodegradable surfactant sodium dodecylbenzene sulfonate (SDBS) were employed, with hydrothermal temperatures maintained below 200 ℃. A standardized waste-management protocol ensured safety and reproducibility. Thirty students were divided into six groups, implementing intragroup role rotation and a group-leader responsibility system. Instructors coordinated progress through structured briefings and resource allocation, enabling parallel execution and cross-validation of results. Hydrothermal temperature was defined as the sole independent variable, while precursor concentration, pH, and reaction time were strictly controlled. Students conducted broad-range screening followed by refined sampling near the phase-transition region, yielding 19 experimental conditions at eight temperatures. Four progressive inquiry modules (color variation, bandgap evolution, the role of SDBS, and the adsorption–photocatalysis relationship) were embedded throughout synthesis, characterization, and performance evaluation. Instruction was limited to targeted questioning at critical stages to facilitate students’ autonomous construction of structure–property relationships. A comprehensive 100-point evaluation system emphasized formative assessment (30%), integrated peer review, instructor observation, written reports, and oral defense.

The framework effectively transformed fragmented experimental steps into a continuous investigative process. Through multi-modal characterization (XRD, SEM, UV–Vis, FTIR, and photocatalytic degradation tests), students independently constructed structure–property relationships, with the majority of students demonstrating this capability. The approach requires only standard laboratory infrastructure and low-toxicity reagents, with high intergroup consistency.

A micro-project-based experimental teaching model centered on BiVO₄ and characterized by single-variable open inquiry, parallel group collaboration, and progressive problem-driven learning was successfully developed. By systematically integrating synthesis, characterization, and performance evaluation and guiding students through structured inquiry pathways, the approach overcomes key limitations of traditional laboratory teaching. With advantages such as safety, low cost, high reproducibility, and scalability, this model provides a practical and transferable framework for advancing materials chemistry laboratory education under the emerging engineering education paradigm.