The global energy crisis, driven by climate change and fossil fuel dependence, necessitates sustainable solutions. MXenes and MBenes, two-dimensional transition metal carbides and borides, emerge as revolutionary photocatalysts for solar-driven energy conversion. Derived from MAX/MAB phases via selective etching, these materials exhibit tunable bandgaps (0.5–2.5 eV), metallic conductivity (>10,000 S/cm), and surface reactivity, enabling efficient visible-light harvesting, charge separation, and catalytic activity. Their integration in hybrid systems enhances hydrogen evolution rates (10-fold improvements) and CO₂-to-fuel conversion selectivity by suppressing charge recombination and stabilizing reaction intermediates. This review analyzes their synthesis, mechanistic roles in water splitting and pollutant degradation, and strategies like heterostructuring to overcome stability and scalability challenges. While MXenes/MBenes bridge renewable energy production with circular economy principles, eco-friendly synthesis and interdisciplinary collaboration remain critical to translating lab-scale innovations into scalable technologies. By addressing material durability and industrial integration, these materials offer a transformative pathway toward decarbonized energy systems, aligning global sustainability goals with advancements in materials science.