In this chapter, the reduction of CO2 and the production of hydrogen by using different noble metals with different techniques have been discussed. The reduction means to reduce the carbon dioxide into CO and other through which the environment gets clean and greenhouse gases will decrease. The reduction mostly occurs through electrolysis process, which involves the chemical reactions to reduce CO2. The carbon dioxide reduction is also known as CO2R. The selectivity of noble metals basically depends upon the facets such as low index and high index facets. Each facet of noble metals has its own properties. The efficiency of the noble metal can be checked through Faradic ratio or Faradic efficiency. The effect of different noble metals on CO2R has been checked. Among all, the gold has higher efficiency in reducing the CO2R but is very expensive. While platinum shows less efficiency toward reduction, it involves the hydrogen evolution reaction (HER) cycle. The HER is the major competing reaction that has to be minimized in order to reduce the CO2. While hydrogen production means to generate hydrogen for fuels and electricity, it can also be done through the electrolysis process. But photocatalysis mechanism is discussed here in order to produce hydrogen. Basically, it involves different catalysts which have different properties of absorbing the light and then initiating the redox reactions, which split the water molecules into hydrogen and oxygen. This hydrogen is then utilized in various applications. Furthermore, different nanomaterials have been studied, among which platinum shows higher efficiency while palladium and copper may serve as a co-catalyst to produce hydrogen. The reduction of CO2 and production of hydrogen are two interlinked processes that have been discussed in the chapter.