Yes, the MAX30101 can be used to extract the respiratory rate. While traditional methods of respiratory rate measurement involve using a strain gauge to measure the expansion of the chest to measure respiration, the same data can be extracted from the PPG signal by processing the signal via Empirical Mode Decomposition technique which is particularly suitable for wearables.
You may find the following link to be quite helpful: https://ieeexplore.ieee.org/document/7348369