Alternative energy for hydrogen production has been continuously studied in recent years to develop efficient renewable energy in the future. Among various parameters to improve hydrogen production efficiency, composite semiconductors are promising sustainable and environmentally friendly solutions for developing photocatalytic activities. Composite semiconductors including homo-, p–n-, and heterojunction (type-II and S-Scheme) have recently been reported as a crucial strategy due to their intriguing features as suitable band structure, facilitate charge separation, high-redox efficiency, absorption light effectively, ability to work in solar energy, environmentally friendly, and efficient energy source. Series of heterojunction construction photocatalyst g-C3N4 based S-scheme heterojunction, including modifications TiO2/g-C3N4 and CoTiO3/g-C3N4, have been examined in detail as emerging materials owing to their potential to result in excellent capacity for responsive photocatalytic application. The mechanism of S-scheme heterojunction was characterized by radiation XPS, fs-TAS, and surface photovoltage. As far as common semiconductors are concerned, the limited review has focused on composites as one of the most alternative construction ways of advancing hydrogen production. Therefore, this chapter examines several strategies for composite semiconductors to enhance photocatalytic activities in hydrogen production.