The high cost of Pt-based catalysts and the sluggish dynamics of the oxygen reduction reaction （ORR） severely hinder the rapid development of fuel cells, Therefore, the search for inexpensive, non-noble metal cataly...The high cost of Pt-based catalysts and the sluggish dynamics of the oxygen reduction reaction （ORR） severely hinder the rapid development of fuel cells, Therefore, the search for inexpensive, non-noble metal catalysts to substitute Pt-based catalysts has become a critical issue in the ORR research field, As an earth-abundant element, the use of Cu to catalyze the ORR has been explored with the ultimate target of finding a replacement for Pt-based catalysts in fuel cells. This review mainly focuses on recent research progress with Cu-based ORR catalysts and aims to aid readers＇ understanding of the status of development in this field. The review begins with a general update on the state of knowledge pertaining to ORR, This is followed by an overview of recent research based on Cu nanomaterial catalysts, which comprises Cu complexes, compounds, and other structures. Charting the development of Cu-based ORR catalysts shows that designing Cu-based materials to mimic active enzymes is an effective approach for ORR catalysis. By collecting recent developments in the field, we hope that this review will promote further development of Cu-based ORR catalysts and their application in fuel cells.展开更多
Nowadays, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc.. After the use-phase, the electronic devices become electronic was...Nowadays, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc.. After the use-phase, the electronic devices become electronic waste （e-waste）; consequently it is important to consider e-waste as a secondary supply for the recovery of these metals. This paper presents the recovery ofAu, Ag, Cu and Nb from PCBs （printed circuit boards） of discarded computers using leaching column technique. The PCBs were crushed with a hammer mill until reaching a particle size between 3.33 mm to 0.43 mm, Then, it was leached with a sodium cyanide solution in a glass column using the following conditions： sodium cyanide concentration 4 g/L, flux 20 L/d kg PCBs day, pH between 10.5 to 11 and leaching time 15 days. Every day, after leaching, the pregnant solutions passed through a column with activated carbon to complete the closed loop system. The following recoveries were obtained： Au 46.6%, Ag 51.3%, Nb 47.2% and Cu 62.3%. A preliminary technical-economic study shows the feasibility to create a small-scale PCBs recycling plant. The initial investment is on the order of USS155,639, considering the recovered metals from the loaded carbon. The internal rate of return for a 10 years period IRR （internal rate of return） and NPV （net present value） estimated are 27% and US$105,926 respectively.展开更多
基金supported by the National Natural Science Foundation of China(21575134,21275136)
文摘The high cost of Pt-based catalysts and the sluggish dynamics of the oxygen reduction reaction （ORR） severely hinder the rapid development of fuel cells, Therefore, the search for inexpensive, non-noble metal catalysts to substitute Pt-based catalysts has become a critical issue in the ORR research field, As an earth-abundant element, the use of Cu to catalyze the ORR has been explored with the ultimate target of finding a replacement for Pt-based catalysts in fuel cells. This review mainly focuses on recent research progress with Cu-based ORR catalysts and aims to aid readers＇ understanding of the status of development in this field. The review begins with a general update on the state of knowledge pertaining to ORR, This is followed by an overview of recent research based on Cu nanomaterial catalysts, which comprises Cu complexes, compounds, and other structures. Charting the development of Cu-based ORR catalysts shows that designing Cu-based materials to mimic active enzymes is an effective approach for ORR catalysis. By collecting recent developments in the field, we hope that this review will promote further development of Cu-based ORR catalysts and their application in fuel cells.
文摘Nowadays, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc.. After the use-phase, the electronic devices become electronic waste （e-waste）; consequently it is important to consider e-waste as a secondary supply for the recovery of these metals. This paper presents the recovery ofAu, Ag, Cu and Nb from PCBs （printed circuit boards） of discarded computers using leaching column technique. The PCBs were crushed with a hammer mill until reaching a particle size between 3.33 mm to 0.43 mm, Then, it was leached with a sodium cyanide solution in a glass column using the following conditions： sodium cyanide concentration 4 g/L, flux 20 L/d kg PCBs day, pH between 10.5 to 11 and leaching time 15 days. Every day, after leaching, the pregnant solutions passed through a column with activated carbon to complete the closed loop system. The following recoveries were obtained： Au 46.6%, Ag 51.3%, Nb 47.2% and Cu 62.3%. A preliminary technical-economic study shows the feasibility to create a small-scale PCBs recycling plant. The initial investment is on the order of USS155,639, considering the recovered metals from the loaded carbon. The internal rate of return for a 10 years period IRR （internal rate of return） and NPV （net present value） estimated are 27% and US$105,926 respectively.
