Photoelectrocatalysis (PEC) incorporates electrochemical techniques with photocatalysis (PC) to facilitate the separation of the photoelectron-hole produced at semiconductor nanoparticles, leading to enhanced photocatalytic efficiency for various applications. Due to its inherently low cost, non-toxicity and chemical stability, titanium dioxide (TiO2) based PEC devices are considered the most promising system for chemical engineering such as pollution degradation and fuel generation, and PEC sensing. In an attempt to bridge fundamental research and practical applications in chemical engineering and sensing, we herein systematically review recent advances in these PEC systems of different scales. More importantly, we offer a series of rational strategies including cell design, application of electric field photoelectrode morphology manipulation and bandgap engineering to enhance the performance of TiO2-based PEC devices and accelerate the commercialization of the TiO2-based PEC technology in chemical engineering.