CeO_2-x nanorods with intrinsic urease-like activity

Area of Science:

• Materials Science
• Environmental Science
• Biomimicry

Background:

• Urea removal from wastewater is crucial due to its ecotoxicity and large-scale production.
• Conventional industrial urea hydrolysis requires harsh conditions (high temperature and pressure).
• Nature utilizes the enzyme urease for efficient urea breakdown under ambient conditions.

Purpose of the Study:

• To develop an efficient, green urease mimic for urea hydrolysis.
• To investigate the catalytic activity and stability of cerium oxide nanorods (CeO2-x NRs).
• To explore the potential application of CeO2-x NRs in wastewater treatment.

Main Methods:

• Synthesis and characterization of CeO2-x nanorods.
• Catalytic activity assessment of urea hydrolysis under ambient conditions.
• Investigation of surface properties via La doping to tune Ce4+/Ce3+ ratio.
• Stability tests against pH variations and urease inhibitors (e.g., Cu2+).

Main Results:

• CeO2-x NRs demonstrated efficient urease mimicry, catalyzing urea hydrolysis at ambient conditions.
• The catalytic activity (kcat = 9.58 × 101 s-1) was approximately one order of magnitude lower than native jack bean urease.
• La doping influenced catalytic activity by altering surface defects and Lewis acidity.
• CeO2-x NRs exhibited excellent stability across different pH levels and in the presence of strong urease inhibitors like Cu2+.

Conclusions:

• CeO2-x NRs represent the first efficient green urease mimic for ambient urea hydrolysis.
• Their low cost, environmental compatibility, and operational stability make them promising for wastewater treatment.
• This biomimicry approach offers a viable alternative to native enzymes in applications like water processing membranes and filters.